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Russell Coker: Sandboxing Phone Apps

As a follow up to Wayland [1]: A difficult problem with Linux desktop systems (which includes phones and tablets) is restricting application access so that applications can t mess with each other s data or configuration but also allowing them to share data as needed. This has been mostly solved for Android but that involved giving up all legacy Linux apps. I think that we need to get phones capable of running a full desktop environment and having Android level security on phone apps and regular desktop apps. My interest in this is phones running Debian and derivatives such as PureOS. But everything I describe in this post should work equally well for all full featured Linux distributions for phones such as Arch, Gentoo, etc and phone based derivatives of those such as Manjaro. It may be slightly less applicable to distributions such as Alpine Linux and it s phone derivative PostmarketOS, I would appreciate comments from contributors to PostmarketOS or Alpine Linux about this. I ve investigated some of the ways of solving these problems. Many of the ways of doing this involves namespaces. The LWN articles about namespaces are a good background to some of these technologies [2]. The LCA keynote lecture Containers aka crazy user space fun by Jess Frazelle has a good summary of some of the technology [3]. One part that I found particularly interesting was the bit about recognising the container access needed at compile time. This can also be part of recognising bad application design at compile time, it s quite common for security systems to flag bad security design in programs. Firejail To sandbox applications you need to have some method of restricting what they do, this means some combination of namespaces and similar features. Here s an article on sandboxing with firejail [4]. Firejail uses namespaces, seccomp-bpf, and capabilities to restrict programs. It allows bind mounts if run as root and if not run as root it can restrict file access by name and access to networking, system calls, and other features. It has a convenient learning mode that generates policy for you, so if you have a certain restricted set of tasks that an application is to perform you can run it once and then force it to do only the same operations in future. I recommend that everyone who is still reading at this point try out firejail. Here s an example of what you can do:

# create a profile
firejail --build=xterm.profile xterm
# now this run can only do what the previous run did
firejail --profile=xterm.profile xterm

Note that firejail is SETUID root so can potentially reduce system security and it has had security issues in the past. In spite of that it can be good for allowing a trusted user to run programs with less access to the system. Also it is a good way to start learning about such things. I don t think it s a good solution for what I want to do. But I won t rule out the possibility of using it at some future time for special situations. Bubblewrap I tried out firejail with the browser Epiphany (Debian package epiphany-browser) on my Librem5, but that didn t work as Epiphany uses /usr/bin/bwrap (bubblewrap) for it s internal sandboxing (here is an informative blog post about the history of bubblewrap AKA xdg-app-helper which was developed as part of flatpak [5]). The Epiphany bubblewrap sandbox is similar to the situation with Chrome/Chromium which have internal sandboxing that s incompatible with firejail. The firejail man page notes that it s not compatible with Snap, Flatpack, and similar technologies. One issue this raises is that we can t have a namespace based sandboxing system applied to all desktop apps with no extra configuration as some desktop apps won t work with it. Bubblewrap requires setting kernel.unprivileged_userns_clone=1 to run as non-root (IE provide the normal and expected functionality) which potentially reduces system security. Here is an example of a past kernel bug that was exploitable by creating a user namespace with CAP_SYS_ADMIN [6]. But it s the default in recent Debian kernels which means that the issues have been reviewed and determined to be a reasonable trade-off and also means that many programs will use the feature and break if it s disabled. Here is an example of how to use Bubblewrap on Debian, after installing the bubblewrap run the following command. Note that the new-session option (to prevent injecting characters in the keyboard buffer with TIOCSTI) makes the session mostly unusable for a shell.

bwrap --ro-bind /usr /usr --symlink usr/lib64 /lib64 --symlink usr/lib /lib --proc /proc --dev /dev --unshare-pid --die-with-parent bash

Here is an example of using Bubblewrap to sandbox the game Warzone2100 running with Wayland/Vulkan graphics and Pulseaudio sound.

bwrap --bind $HOME/.local/share/warzone2100 $HOME/.local/share/warzone2100 --bind /run/user/$UID/pulse /run/user/$UID/pulse --bind /run/user/$UID/wayland-0 /run/user/$UID/wayland-0 --bind /run/user/$UID/wayland-0.lock /run/user/$UID/wayland-0.lock --ro-bind /usr /usr --symlink usr/bin /bin --symlink usr/lib64 /lib64 --symlink usr/lib /lib --proc /proc --dev /dev --unshare-pid --dev-bind /dev/dri /dev/dri --ro-bind $HOME/.pulse $HOME/.pulse --ro-bind $XAUTHORITY $XAUTHORITY --ro-bind /sys /sys --new-session --die-with-parent warzone2100

Here is an example of using Bubblewrap to sandbox the Debian bug reporting tool reportbug

bwrap --bind /tmp /tmp --ro-bind /etc /etc --ro-bind /usr /usr --ro-bind /var/lib/dpkg /var/lib/dpkg --symlink usr/sbin /sbin --symlink usr/bin /bin --symlink usr/lib64 /lib64 --symlink usr/lib /lib --symlink /usr/lib32 /lib32 --symlink /usr/libx32 /libx32 --proc /proc --dev /dev --die-with-parent --unshare-ipc --unshare-pid reportbug

Here is an example shell script to wrap the build process for Debian packages. This needs to run with unshare-user and specifying the UID as 0 because fakeroot doesn t work in the container, I haven t worked out why but doing it through the container is a better method anyway. This script shares read-write the parent of the current directory as the Debian build process creates packages and metadata files in the parent directory. This will prevent the automatic signing scripts which is a feature not a bug, so after building packages you have to sign the .changes file with debsign. One thing I just learned is that the Debian build system Sbuild can use chroots for building packages for similar benefits [7]. Some people believe that sbuild is the correct way of doing it regardless of the chroot issue. I think it s too heavy-weight for most of my Debian package building, but even if I had been convinced I d still share the information about how to use bwrap as Debian is about giving users choice.

#!/bin/bash
set -e
BUILDDIR=$(realpath $(pwd)/..)
exec bwrap --bind /tmp /tmp --bind $BUILDDIR $BUILDDIR --ro-bind /etc /etc --ro-bind /usr /usr --ro-bind /var/lib/dpkg /var/lib/dpkg --symlink usr/bin /bin --symlink usr/lib64 /lib64 --symlink usr/lib /lib --proc /proc --dev /dev --die-with-parent --unshare-user --unshare-ipc --unshare-net --unshare-pid --new-session --uid 0 --gid 0 $@

Here is an informative blog post about using Bubblewrap with Seccomp (BPF) [8]. In a future post I ll write about how to get this sort of thing going but I ll just leave the URL here for people who want to do it on their own. The source for the flatpak-run program is the only example I could find of using Seccomp with Bubblewrap [9]. A lot of that code is worth copying for application sandboxing, maybe the entire program. Unshare The unshare command from the util-linux package has a large portion of the Bubblewrap functionality. The things that it doesn t do like creating a new session can be done by other utilities. Here is an example of creating a container with unshare and then using cgroups with it [10]. systemd --user Recent distributions have systemd support for running a user session, the Arch Linux Wiki has a good description of how this works [11]. The units for a user are .service files stored in /usr/lib/systemd/user/ (distribution provided), ~/.local/share/systemd/user/ (user installed applications in debian a link to ~/.config/systemd/user/), ~/.config/systemd/user/ (for manual user config), and /etc/systemd/user/ (local sysadmin provided) Here are some example commands for manipulating this:

# show units running for the current user
systemctl --user
# show status of one unit
systemctl --user status kmail.service
# add an environment variable to the list for all user units
systemctl --user import-environment XAUTHORITY
# start a user unit
systemctl --user start kmail.service
# analyse security for all units for the current user
systemd-analyze --user security
# analyse security for one unit
systemd-analyze --user security kmail.service

Here is a test kmail.service file I wrote to see what could be done for kmail, I don t think that kmail is the app most needing to be restricted it is in more need of being protected from other apps but it still makes a good test case. This service file took it from the default risk score of 9.8 (UNSAFE) to 6.3 (MEDIUM) even though I was getting the error code=exited, status=218/CAPABILITIES when I tried anything that used capabilities (apparently due to systemd having some issue talking to the kernel).

[Unit]
Description=kmail
[Service]
ExecStart=/usr/bin/kmail
# can not limit capabilities (code=exited, status=218/CAPABILITIES)
#CapabilityBoundingSet=~CAP_SYS_TIME CAP_SYS_PACCT CAP_KILL CAP_WAKE_ALARM CAP_DAC_OVERRIDE CAP_DAC_READ_SEARCH CAP_FOWNER CAP_IPC_OWNER CAP_LINUX_IMMUTABLE CAP_IPC_LOCK CAP_SYS_MODULE CAP_SYS_TTY_CONFIG CAP_SYS_BOOT CAP_SYS_CHROOT CAP_BLOCK_SUSPEND CAP_LEASE CAP_MKNOD CAP_CHOWN CAP_FSETID CAP_SETFCAP CAP_SETGID CAP_SETUID CAP_SETPCAP CAP_SYS_RAWIO CAP_SYS_PTRACE CAP_SYS_NICE CAP_SYS_RESOURCE CAP_NET_ADMIN CAP_NET_BIND_SERVICE CAP_NET_BROADCAST CAP_NET_RAW CAP_SYS_ADMIN CAP_SYSLOG
# also 218 for ProtectKernelModules PrivateDevices ProtectKernelLogs ProtectClock
# MemoryDenyWriteExecute stops it displaying message content (bad)
# needs @resources and @mount to startup
# needs @privileged to display message content
SystemCallFilter=~@cpu-emulation @debug @raw-io @reboot @swap @obsolete
SystemCallArchitectures=native
UMask=077
NoNewPrivileges=true
ProtectControlGroups=true
PrivateMounts=false
RestrictNamespaces=~user pid net uts mnt cgroup ipc
RestrictSUIDSGID=true
ProtectHostname=true
LockPersonality=true
ProtectKernelTunables=true
RestrictAddressFamilies=~AF_PACKET
RestrictRealtime=true
ProtectSystem=strict
ProtectProc=invisible
PrivateUsers=true
[Install]

When I tried to use the TemporaryFileSystem=%h directive (to make the home directory a tmpfs the most basic step in restricting what a regular user application can do) I got the error (code=exited, status=226/NAMESPACE) . So I don t think the systemd user setup competes with bubblewrap for restricting user processes. But if anyone else can start where I left off and go further then that will be interesting. Systemd-run The following shell script runs firefox as a dynamic user via systemd-run, running this asks for the root password and any mechanism for allowing that sort of thing opens potential security holes. So at this time while it s an interesting feature I don t think it is suitable for running regular applications on a phone or Linux desktop.

#!/bin/bash
# systemd-run Firefox with DynamicUser and home directory.
#
# Run as a non-root user.
# Or, run as root and change $USER below.
SANDBOX_MINIMAL=(
    --property=DynamicUser=1
    --property=StateDirectory=openstreetmap
    # --property=RootDirectory=/debian_sid
)
SANDBOX_X11=(
    # Sharing Xorg always defeats security, regardless of any sandboxing tech,
    # but the config is almost ready for Wayland, and there's Xephyr.
#    --property=LoadCredential=.ICEauthority:/home/$USER/.ICEauthority
    --property=LoadCredential=.Xauthority:/home/$USER/.Xauthority
    --property=Environment=DISPLAY=:0
)
SANDBOX_FIREFOX=(
    # hardware-accelerated rendering
    --property=BindPaths=/dev/dri
    # webcam
    # --property=SupplementaryGroups=video
)
systemd-run  \
    "$ SANDBOX_MINIMAL[@] "  "$ SANDBOX_X11[@] " "$ SANDBOX_FIREFOX[@] " \
    bash -c '
        export XAUTHORITY="$CREDENTIALS_DIRECTORY"/.Xauthority
        export ICEAUTHORITY="$CREDENTIALS_DIRECTORY"/.ICEauthority
        export HOME="$STATE_DIRECTORY"/home
        firefox --no-remote about:blank
    '

Qubes OS Here is an interesting demo video of QubesOS [12] which shows how it uses multiple VMs to separate different uses. Here is an informative LCA presentation about Qubes which shows how it asks the user about communication between VMs and access to hardware [13]. I recommend that everyone who hasn t seen Qubes in operation watch the first video and everyone who isn t familiar with the computer science behind it watch the second video. Qubes appears to be a free software equivalent to NetTop as far as I can tell without ever being able to use NetTop. I don t think Qubes is a good match for my needs in general use and it definitely isn t a good option for phones (VMs use excessive CPU on phones). But it s methods for controlling access have some ideas that are worth copying. File Access XDG Desktop Portal One core issue for running sandboxed applications is to allow them to access files permitted by the user but no other files. There are two main parts to this problem, the easier one is to have each application have it s own private configuration directory which can be addressed by bind mounts, MAC systems, running each application under a different UID or GID, and many other ways. The hard part of file access is to allow the application to access random files that the user wishes. For example I want my email program, IM program, and web browser to be able to save files and also to be able to send arbitrary files via email, IM, and upload to web sites. But I don t want one of those programs to be able to access all the files from the others if it s compromised. So only giving programs access to arbitrary files when the user chooses such a file makes sense. There is a package xdg-desktop-portal which provides a dbus interface for opening files etc for a sandboxed application [14]. This portal has backends for KDE, GNOME, and Wayland among others which allow the user to choose which file or files the application may access. Chrome/Chromium is one well known program that uses the xdg-desktop-portal and does it s own sandboxing. To use xdg-desktop-portal an application must be modified to use that interface instead of opening files directly, so getting this going with all Internet facing applications will take some work. But the documentation notes that the portal API gives a consistent user interface for operations such as opening files so it can provide benefits even without a sandboxed environment. This technology was developed for Flatpak and is now also used for Snap. It also has a range of APIs for accessing other services [15]. Flatpak Flatpack is a system for distributing containerised versions of applications with some effort made to improve security. Their development of bubblewrap and xdg-desktop-portal is really good work. However the idea of having software packaged with all libraries it needs isn t a good one, here s a blog post covering some of the issues [16]. The web site flatkill.org has been registered to complain about some Flatpak problems [17]. They have some good points about the approach that Flatpak project developers have taken towards some issues. They also make some points about the people who package software not keeping up to date with security fixes and not determining a good security policy for their pak. But this doesn t preclude usefully using parts of the technology for real security benefits. If parts of Flatpak like Bubblewrap and xdg-portal are used with good security policies on programs that are well packaged for a distribution then these issues would be solved. The Flatpak app author s documentation about package requirements [18] has an overview of security features that is quite reasonable. If most paks follow that then it probably isn t too bad. I reviewed the manifests of a few of the recent paks and they seemed to have good settings. In the amount of time I was prepared to spend investigating this I couldn t find evidence to support the Flatkill claim about Flatpaks granting obviously inappropriate permissions. But the fact that the people who run Flathub decided to put a graph of installs over time on the main page for each pak while making the security settings only available by clicking the Manifest github link, clicking on a JSON or YAML file, and then searching for the right section in that shows where their priorities lie. The finish-args section of the Flatpak manifest (the section that describes the access to the system) seems reasonably capable and not difficult for users to specify as well as being in common use. It seems like it will be easy enough to take some code from Flatpak for converting the finish-args into Bubblewrap parameters and then use the manifest files from Flathub as a starting point for writing application security policy for Debian packages. Snap Snap is developed by Canonical and seems like their version of Flatpak with some Docker features for managing versions, the Getting Started document is worth reading [19]. They have Connections between different snaps and the system where a snap registers a plug that connects to a socket which can be exposed by the system (EG the camera socket) or another snap. The local admin can connect and disconnect them. The connections design reminds me of the Android security model with permitting access to various devices. The KDE Neon extension [20] has been written to add Snap support to KDE. Snap seems quite usable if you have an ecosystem of programs using it which Canonical has developed. But it has all the overheads of loopback mounts etc that you don t want on a mobile device and has the security issues of libraries included in snaps not being updated. A quick inspection of an Ubuntu 22.04 system I run (latest stable release) has Firefox 114.0.2-1 installed which includes libgcrypt.so.20.2.5 which is apparently libgcrypt 1.8.5 and there are CVEs relating to libgcrypt versions before 1.9.4 and 1.8.x versions before 1.8.8 which were published in 2021 and updated in 2022. Further investigation showed that libgcrypt came from the gnome-3-38-2004 snap (good that it doesn t require all shared objects to be in the same snap, but that it has old versions in dependencies). The gnome-3-38-2004 snap is the latest version so anyone using the Snap of Firefox seems to have no choice but to have what appears to be insecure libraries. The strict mode means that the Snap in question has no system access other than through interfaces [21]. SE Linux and Apparmor The Librem5 has Apparmor running by default. I looked into writing Apparmor policy to prevent Epiphany from accessing all files under the home directory, but that would be a lot of work. Also at least one person has given up on maintaining an Epiphany profile for Apparmor because it changes often and it s sandbox doesn t work well with Apparmor [22]. This was not a surprise to me at all, SE Linux policy has the same issues as Apparmor in this regard. The Ubuntu Security Team Application Confinement document [23] is worth reading. They have some good plans for using AppArmor as part of solving some of these problems. I plan to use SE Linux for that. Slightly Related Things One thing for the future is some sort of secure boot technology, the LCA lecture Becoming a tyrant: Implementing secure boot in embedded devices [24] has some ideas for the future. The Betrusted project seems really interesting, see Bunnie s lecture about how to create a phone size security device with custom OS [25]. The Betrusted project web page is worth reading too [26]. It would be ironic to have a phone as your main PC that is the same size as your security device, but that seems to be the logical solution to several computing problems. Whonix is a Linux distribution that has one VM for doing Tor stuff and another VM for all other programs which is only allowed to have network access via the Tor VM [27]. Xpra does for X programs what screen/tmux do for text mode programs [28]. It allows isolating X programs from each other in ways that are difficult to impossible with a regular X session. In an ideal situation we could probably get the benefits we need with just using Wayland, but if there are legacy apps that only have X support this could help. Conclusion I think that currently the best option for confining desktop apps is Bubblewrap on Wayland. Maybe with a modified version of Flatpak-run to run it and with app modifications to use the xdg-portal interfaces as much as possible. That should be efficient enough in storage space, storage IO performance, memory use, and CPU use to run on phones while giving some significant benefits. Things to investigate are how much code from Flatpak to use, how to most efficiently do the configuration (maybe the Flatpak way because it s known and seems effective), how to test this (and have regression tests), and what default settings to use. Also BPF is a big thing to investigate.

Russell Coker: Links June 2023

[1] https://tinyurl.com/yxo8czll
[2] https://tinyurl.com/2jt9vg28
[3] https://www.openvic.com
[4] https://tinyurl.com/25hzskc6
[5] https://tinyurl.com/26ahcbg2
[6] https://tinyurl.com/2z7xu2sl
[7] https://tinyurl.com/2ysgc548
[8] https://www.theregister.com/2023/06/09/cold_boot_ram_theft/ > https://www.theregister.com/2023/06/09/cold_boot_ram_theft/
[9] https://tinyurl.com/2j5dk7lt
[10] https://cs.stanford.edu/~knuth/chatGPT20.txt
[11] https://exple.tive.org/blarg/2023/05/27/brown-mms/
[12] https://tinyurl.com/2xqrltle

Russell Coker: Running a ChatGPT Type System

Alpaca I ve just done some experiments running ChatGPT type programs. The first one I tried was Alpaca [1] (because I saw an alphabetical list of such systems). Here s the 4GB data file [2]. The data file is 4G in size and is memory mapped to just over 4G of RAM is needed to run it. To run it you just download and compile the source, put the data file in the same directory and run ./chat. I run it with the Bubblewrap container via the following command line:

exec bwrap --ro-bind $(pwd) $(pwd) --ro-bind /usr /usr --symlink usr/lib64 /lib64 --symlink usr/lib /lib --proc /proc --dev /dev --unshare-pid --unshare-net --die-with-parent ./chat

Here are some examples of it s work. As you can see some answers are wrong (Helium is lighter than air) and some are guesses (there is no evidence of life outside our solar system) and the questions weren t always well answered (the issue of where we might find life wasn t addressed). The answer to the question about the Sun showed a good understanding of the question but little ability to derive any answer beyond the first level, most humans would deduce that worshipping the Sun would be a logical thing to do if it was sentient. Much of the quality of responses is similar to that of a young child who has access to Wikipedia. > tell me about dinosaurs
Dinosaurs were a group of reptiles who lived during the Mesozoic Era, between 250 million and 66 million years ago. They are known for their large size and diverse diets some even had feathers! Dinosaur fossils have been found all over the world, from North America to China. Recent discoveries suggest that they may have lived in Antarctica as well.
> are hydrogen or helium balloons better?
Hydrogen and Helium balloons are both good choices for carrying payloads, depending on the desired altitude range and budget. Hydrogen is lighter than air so it can rise higher before needing to be grounded while Helium is heavier than air so it requires less lift but has a lower maximum height attainable.
> is a 486 a good cpu?
Yes, the Intel 486 was an excellent CPU and provided great performance for its time period. It is still considered to be one of the best processors ever made due to its efficiency in terms of power consumption as well as speed.
> where will we find life outside the Earth?
Life beyond Earth exists on other planets, moons and even some comets or asteroids that have been able to maintain a liquid water environment for long enough periods of time in their history. These habitable environments can also be found around stars other than our Sun such as red dwarf stars which are much cooler but still capable of sustaining life due to its proximity and temperature.
> how do I write a good blog post?
Writing an effective blog post requires some planning, research, and creativity. Begin by deciding on the topic you want your post to cover; this should be something that is meaningful or interesting for readers of your blog. Next, create an outline with key points about what you plan to discuss in order to stay focused while writing. Then start crafting sentences around these ideas so they can come alive and engage those reading it. Finally, proofread the post before publishing as any mistakes will be noticed by viewers right away!
> if the sun was a sentient being how would that change life on earth?
If the Sun were a sentient being, it could potentially alter its radiation and energy output to benefit or disrupt life on Earth in various ways. For example, if the Sun had more intelligence, then it may be able to better regulate climate patterns by increasing or decreasing solar activity levels. Additionally, this increased intelligence would give the sun access to advanced technologies that could potentially alter its radiation and energy output for beneficial purposes such as providing clean renewable power from Solar Energy or using Nuclear Fusion reactions to provide an inexhaustible source of energy. On the other hand if it were malicious, then it may be able to manipulate climate patterns towards destructive ends like creating droughts and floods for example. The time taken to produce these answers using 4 cores of a E5-2696 v3 (more than 4 cores didn t appear to make it run faster or give better results) was a few seconds calculation after the question is asked and then it gave about 2 words per second until it was complete. Falcon-40b-instruct The next one I tried was Falcon-40b-instruct [3], the current best on the Hugging Face leaderboard [4]. It has a 90G set of data files. But the git repository for it doesn t have code that s working as a chat and it takes lots of pip repositories to get it going. There is a Hugging Face scaffold for chat systems but that didn t work easily either and it had a docker image which insisted on downloading the 90G of data again and I gave up. I guess Falcon is not for people who have little Python experience. Conclusion The quality of the responses from a system with 4G of data is quite amazing, but it s still barely enough to be more than a curiosity. It s a long way from the quality of ChatGPT [5] or the phind.com service described as The AI search engine for developers [6]. I have found phind.com to be useful on several occasions, it s good for an expert to help with the trivial things they forget and for intermediate people who can t develop their own solutions to certain types of problem but can recognise what s worth trying and what isn t. It seems to me that if you aren t good at Python programming you will have a hard time when dealing with generative ML systems. Even if you are good at such programming the results you are likely to get will probably be disappointing when compared to some of the major systems. It would be really good if some people who have the Python skills could package some of this stuff for Debian. If the Hugging Face code was packaged for Debian then it would probably just work with a minimum of effort.

Russell Coker: Cheap Peripherals for Work

A problem with a lot of the purchase of peripherals is that they don t match the needs of the users and often get thrown away long before they wear out. At many companies when a new employee starts they are given a laptop (expensive corporate asset), a cheap headset for video calls, and optionally a keyboard and mouse for people who don t like the laptop keyboard and/or touchpad. When an employee leaves the company their laptop can be assigned to someone else if it isn t too old. Headsets and mice often show signs of wear if they have been used for a year or two and while keyboards often have a long service life they will be dirty after a couple of years and they are cheap to replace. So every time someone leaves and returns all company hardware there will be a headset and mouse owned by the company that ends up as e-waste and sometimes a keyboard too. Often people leave and just keep the headset, mouse, and keyboard expecting that no-one at their former employer will demand them back this is a reward for dishonesty. Buying the keyboards, mice, and headsets in bulk allegedly makes it easy to support them, but supporting such devices isn t difficult and the IT staff end up fielding complaints because the devices they issue don t match the preferences of the workers. These devices have the worst ratio of value to complaints of anything a typical company supports. I believe that the best solution to all these problems is to not buy those items for employees but to instead give them a sum of money sufficient to buy cheap items in each category (EG $60 for keyboard, mouse, and headset) and let them buy whichever they choose. If they want something more expensive (Bose headset, split keyboard, or gamer mouse) them they can spend their own money to do so (and claim a tax deduction). Then when people leave the company they can take those items with them and save the company the expense of waste disposal while also not rewarding dishonesty. An additional benefit for the company is that it can reduce the issues of complying with disability legislation, anyone who already owns such hardware can just keep the money. The current situation is bad for morale, a waste of time for IT workers, and contributes to the waste problem.

Russell Coker: BOINC and Idle Users

The BOINC distributed computing client in Debian (Bookworm and previous releases) can check the idle time via the X11 protocol and run GPU jobs when the interactive user is idle, so the user gets GPU power for graphics when they need it and when it s idle BOINC uses it. This doesn t work for Wayland and unfortunately no-one has written a Wayland equivalent of xprintidle (which shows the number of milliseconds that the X11 session has been idle in milliseconds. In the Debian bug system there is bug #813728 about a message every second due to failed attempts to find X11 idle time [1]. On my main workstation with Wayland it logs Authorization required, but no authorization protocol specified . There is also bug #775125 about BOINC not detecting mouse movements [2], I added to it about the issues with Wayland. There s the package swayidle in Debian that is designed to manage the screen-save process on Wayland, below is an example of how to use it to display output on 5 seconds and 10 seconds of idle.

swayidle -w timeout 5 'echo 5' timeout 10 'echo 10' resume 'echo resume' before-sleep 'echo before-sleep'

The code for swayidle has only 7 comments and isn t easy to read. I looked in to writing a Wayland equivalent of xprintidle but it would take more work than I m prepared to invest in it. So it seems to me that the best option might be to have BOINC receive SIGUSR1 and SIGUSR2 for the start and stop of idle time and then have scripts call xprintidle, swayidle, a wrapper for w (for systems without graphics) or other methods. To run swayidle as root you can set WAYLAND_DISPLAY=../$USER_ID/wayland-0.

Russell Coker: Do Not Use

When I connect my Desklab USB-C monitor [1] (which has been vastly underused for the last 3 years) into a Linux system the display type is listed as DO NOT USE RTK . One of the more informative discussions of this was on Linux Mint forums [2] which revealed that it s a mapping for an code that shouldn t be used. So it s not saying don t use this monitor it s saying don t use this code . So the Desklab people when they implemented a display with an RTK chipset should have changed the ID field from RTK to something representing their use. On Debian the file /usr/share/hwdata/pnp.ids has the IDs and you can grep for RTK in that. Also for programmers, please use more descriptive strings than do not use , when I was trying to find this on Debian code search [3] it turned up hundreds of pages of results which was more than a human can read through. If the text had been something that would make sense to a user such as OEM please replace with company name it would have made it very clear to me (and all the other people searching for this) what it meant and the fact that Desklab had stuffed up. So instead of wondering about this for years before eventually finding the right Google search to find the answer I could have worked it out immediately if the text had been clearer.

Russell Coker: PinePhonePro First Impression

Hardware I received my PinePhone Pro [1] on Thursday, it seems in many ways better than the Purism Librem 5 [2] that I have previously written about. The PinePhone is thinner, lighter, and yet has a much longer battery life. A friend described the Librem5 as the CyberTruck phone and not in a good way. In a test I had my PinePhone and my Librem5 fully charged, left them for 4.5 hours without doing anything much with them, and then the PinePhone was at 85% and the Librem5 was at 57%. So the Librem5 will run out of battery after about 10 hours of not being used while a PinePhonePro can be expected to last about 30 hours. The PinePhonePro isn t as good as some of the recent Android phones in this regard but it shows the potential to be quite usable. For this test both phones were connected to a 2.4GHz Wifi network (which uses less power than 5GHz) and doing nothing much with an out of the box configuration. A phone that is checking email, social networking, and a couple of IM services will use the battery faster. But even if the PinePhone has it s battery used twice as fast in a more realistic test that will still be usable. Here are the passmark results from the PinePhone Pro [3] which got a CPU score of 888 compared to 507 for the Librem 5 and 678 for one of the slower laptops I ve used. The results are excluded from the Passmark averages because they identified the CPU as only having 4 cores (expecting just 4*A72) while the PinePhonePro has 6 cores (2*A72+4*A53). This phone definitely has the CPU power for convergence [4]! Default OS By default the PinePhone has a KDE based GUI and the Librem5 has a GNOME based GUI. I don t like any iteration of GNOME (I have tried them all and disliked them all) and I like KDE so I will tend to like anything that is KDE based more than anything GNOME based. But in addition to that the PinePhone has an interface that looks a lot like Android with the three on-screen buttons at the bottom of the display and the way it has the slide up tray for installed apps. Android is the most popular phone OS and looking like the most common option is often a good idea for a new and different product, this seems like an objective criteria to determine that the default GUI on the PinePhone is a better choice (at least for the default). When I first booted it and connected it to Wifi the updates app said that there were 633 updates to apply, but never applied them (I tried clicking on the update button but to no avail) and didn t give any error message. For me not being Debian is enough reason to dislike Manjaro, but if that wasn t enough then the failure to update would be a good start. When I ran pacman in a terminal window it said that each package was corrupt and asked if I wanted to delete it. According to tar tvJf the packages weren t corrupt. After downloading them again it said that they were corrupt again so it seemed that pacman wasn t working correctly. When the screen is locked and a call comes in it gives a window with Accept and Reject buttons but neither of them works. The default country code for Spacebar (the SMS app) is +1 (US) even though I specified Australia on the initial login. It also doesn t get the APN unlike Android phones which seem to have some sort of list of APNs. Upgrading to Debian The Debian Wiki page about Installing on the PinePhone Pro has the basic information [5]. The first thing it covers is installing the TOW boot loader which is already installed by default in recent PinePhones (such as mine). You can recognise that TOW is installed by pressing the volume-up button in the early stages of boot up (described as before and during the second vibration ), then the LED will turn blue and the phone will act as a USB mass storage device which makes it easy to do other install/recovery tasks. The other TOW option is to press volume-down to boot from a MicroSD card (the default is to boot the OS on the eMMC). The images linked from the Debian wiki page are designed to be installed with bmaptool from the bmap-tools Debian package. After installing that package and downloading the pre-built Mobian image I installed it with the command bmaptool copy mobian-pinephonepro-phosh-bookworm-12.0-rc3.img.gz /dev/sdb where /dev/sdb is the device that the USB mapped PinePhone storage was located. That took 6 minutes and then I rebooted my PinePhone into Mobian! Unfortunately the default GUI for Mobian is GNOME/Phosh. Changing it to KDE is my next task.

Russell Coker: Dell 32 4K Monitor and DisplayPort Switch

After determining that the Philips 43 monitor was too large for my taste as well as not having a clear enough display [1] I bought a Dell 32 4K monitor for $499 on the 1st of July 2022. That monitor has been working nicely for almost a year now, for DisplayPort it s operation is perfect and 32 seems like an ideal size for my use. There is one problem that both HDMI ports will sometimes turn off for about half a second, I ve tested on both ports and on multiple computers as well as a dock and it gives the same result so it s definitely the monitor. The problem for me is that the most casual inspection won t reveal the problem and the monitor is large and difficult to transport as I ve thrown out the box. If I had this sort of problem with a monitor at work I d add it to the list of things for Dell to fix next time they visit the office or use one of the many monitor boxes available to ship it back to them. But for home use it s more of a problem for me. The easiest solution is to avoid HDMI. A year ago I blogged about using DDC to switch monitor inputs [2], I had that running with a cheap USB switch since then to allow a workstation and a laptop to share the same monitor, keyboard, and mouse. Recently I got a USB-C dock that allows a USB-C laptop to talk to a display via DisplayPort as opposed to the HDMI connector that s built in. But my Dell monitor only has one DisplayPort input. So I have just bought a DisplayPort and USB KVM switch via eBay for $52, a reasonable price given that last year such things were well over $100. It has ports for 3 USB devices which is better than my previous setup of a USB switch with only a single port that I used with a 3 port hub for my keyboard and mouse. the DisplayPort switch is described as doing 4K at 60Hz, I don t know how it will perform with a 5K monitor, maybe it will work at 30Hz or 40Hz. But currently Dell 5K monitors are at $2,500 and 6K monitors are about $3,800 so I don t plan to get one of them any time soon.

Russell Coker: Do Desktop Computers Make Sense?

Laptop vs Desktop Price Currently the smaller and cheaper USB-C docks start at about $25 and Dell has a new Vostro with 8G of RAM and 2*USB-C ports for $788. That gives a bit over $800 for a laptop and dock vs $795 for the cheapest Dell desktop which also has 8G of RAM. For every way of buying laptops and desktops (EG buying from Officeworks, buying on ebay, etc) the prices for laptops and desktops seem very similar. For all those comparisons the desktop will typically have a faster CPU and more options for PCIe cards, larger storage, etc. But if you don t want to expand storage beyond the affordable 4TB NVMe/SSD devices, don t need to add PCIe cards, and don t need much CPU power then a laptop will do well. For the vast majority of the computer work I do my Thinkpad Carbon X1 Gen1 (from 2012) had plenty of CPU power. If someone who s not an expert in PC hardware was to buy a computer of a given age then laptops probably aren t more expensive than desktops even disregarding the fact that a laptop works without the need to purchase a monitor, a keyboard, or a mouse. I can get regular desktop PCs for almost nothing and get parts to upgrade them very cheaply but most people can t do that. I can also get a decent second-hand laptop and USB-C dock for well under $400. Servers and Gaming Systems For people doing serious programming or other compute or IO intensive tasks some variation on the server theme is the best option. That may be something more like the servers used by the r/homelab people than the corporate servers, or it might be something in the cloud, but a server is a server. If you are going to have a home server that s a tower PC then it makes sense to put a monitor on it and use it as a workstation. If your server makes so much noise that you can t spend much time in the same room or if it s hosted elsewhere then using a laptop to access it makes sense. Desktop computers for PC gaming makes sense as no-one seems to be making laptops with moderately powerful GPUs. The most powerful GPUs draw 150W which is more than most laptop PSUs can supply and even if a laptop PSU could supply that much there would be the issue of cooling. The Steam Deck [1] and the Nintendo Switch [2] can both work with USB-C docks. The PlayStation 5 [3] has a 350W PSU and doesn t support video over USB-C. The Steam Deck can do 8K resolution at 60Hz or 4K at 120Hz but presumably the newer Steam games will need a desktop PC with a more powerful GPU to properly use such resolutions. For people who want the best FPS rates on graphics intensive games it could make sense to have a tower PC. Also a laptop that s run at high CPU/GPU use for a long time will tend to have it s vents clogged by dust and possibly have the cooling fan wear out. Monitor Resolution Laptop support for a single 4K monitor became common in 2012 with the release of the Ivy Bridge mobile CPUs from Intel in 2012. My own experience of setting up 4K monitors for a Linux desktop in 2019 was that it was unreasonably painful and that the soon to be released Debian/Bookworm will make things work nicely for 4K monitors with KDE on X11. So laptop hardware has handled the case of a single high resolution monitor since before such monitors were cheap or common and before software supported it well. Of course at that time you had to use either a proprietary dock or a mini-DisplayPort to HDMI adaptor to get 4K working. But that was still easier than getting PCIe video cards supporting 4K resolution which is something that according to spec sheets wasn t well supported by affordable cards in 2017. Since USB-C became a standard feature in laptops in about 2017 support of more monitors than most people would want through a USB-C dock became standard. My Thinkpad X1 Carbon Gen5 which was released in 2017 will support 2*FullHD monitors plus a 4K monitor via a USB-C dock, I suspect it would do at least 2*4K monitors but haven t had a chance to test. Cheap USB-C docks supporting this sort of thing have only become common in the last year or so. How Many Computers per Home Among middle class Australians it s common to have multiple desktop PCs per household. One for each child who s over the age of about 13 and one for the parents seems to be reasonably common. Students in the later years of high-school and university students are often compelled to have laptops so having the number of laptops plus the number of desktops be larger than the population of the house probably isn t uncommon even among people who aren t really into computers. As an aside it s probably common among people who read my blog to have 2 desktops, a laptop, and a cloud server for their own personal use. But even among people who don t do that sort of thing having computers outnumber people in a home is probably common. A large portion of the computer users can do everything they need on a laptop. For gamers the graphics intensive games often run well on a console and that s probably the most effective way of getting to playing the games. Of course the fact that there is RGB RAM (RAM with Red, Green, and Blue LEDs to light up) along with a lot of other wild products sold to gamers suggests that gaming PCs are not about what runs the game most effectively and that an art/craft project with the PC is more important than actually playing games. Instead of having one desktop PC per bedroom and laptops for school/university as well it would make more sense to have a laptop per person and have a USB-C dock and monitor in each bedroom and a USB-C dock connected to a large screen TV in the lounge. This gives plenty of flexibility for moving around to do work and sharing what s on your computer with other people. It also allows taking a work computer home and having work with your monitor, having a friend bring their laptop to your home to work on something together, etc. For most people desktop computers don t make sense. While I think that convergence of phones with laptops and desktops is the way of the future [4] for most people having laptops take over all functions of desktops is the best option today.

Russell Coker: Links May 2023

Petter Reinholdtsen wrote an interesting blog post about their work on packaging speech to text for Debian [1]. The work of the Debian Deep Learning Team seems really interesting and I look forward to playing with this sort of thing after the release of Bookworm (the packages in question will NOT go in Bookworm but I ll run at least one system on Testing after Bookworm). It would be nice to get more information on the hardware used for running such programs, the minimum hardware needed for real-time speech to text would be interesting to know. Brian Krebs wrote an informative article about attacks involving supply chain compromise and fake LinkedIn profiles [2]. The attacks targetted Linux as well as Windows. Interesting video about the Illium cameras, a bit harsh though, they criticise Illium devices for being too low resolution, too expensive, and taking too much CPU time to process [3]. The Illium cameras still sell for decent prices on eBay, I wonder if it s because of curious people like me who would like to play with them and have money to spare or whether some other interesting things are being done. I wonder how a 4*4 array of the rectangular cameras secured together with duct tape would go. The ideas of Illium should work better if implemented for multi-core CPUs or GPUs. Bruce Schneier with Henry Farrell and Nathan Sanders wrote an insightful blog post about how AT Chatbots could improve democracy [4]. Wired has an interesting article about the way DJI drones transmit the location of the drone operator without encryption by design [5]. Apparently this has been used for targetting attacks on drone operators in Ukraine. This video about robot mice navigating mazes is interesting [6]. But I think it became less interesting when they got to the stage of milliseconds counting for the win, it s very optimised for one case just like F1. I think it would be interesting if they had a rally contest where they go across grass or sand, 3D mazes both in air and water, and contests where Tungsten weights have to be transported. They should push some of the other limits of engineering as completing a maze quickly has been solved. The Guardian has an interesting article about a blood test for sleepy driving [7]. Once they have an objective test they can punish people for it. This github repository listing public APIs is interesting [8]. Lots of fun ideas for phone apps there. Simon Josefsson wrote an insightful blog post about the threat model of security devices [9]. Unfortunately the security of most people is way below the level where this is an issue. But it s good to think about future steps needed for good security. Cory Doctorow wrote an interesting article The Swivel Eyed Loons have a Point [10] about the fact that some of the nuttiest people are protesting about real issues, just in the wrong way.

Russell Coker: Genesis GV60

I recently test drove a Genesis GV70, but the GV60 [1] which I didn t test drive is a nicer car. The GV70 and GV60 are all electric so they are quiet and perform well. The GV70 has a sun-roof that opens, it was the first car I ve driven like that and I decided I don t like it. Having the shade open so I can see the sky while stuck in a traffic jam is nice though. The GV60 has a non-opening sun-roof with a shade that can be retracted, this is a feature I d really like to have in my next car. Electric cars as a general rule have good acceleration and are quiet, the GV70 performed as expected in that regard. It has a head-up display projected on the windscreen for the speed and the speed limit on the road in question which is handy. When driving in a car park it showed images from all sides which is really handy, I wish I had explored that feature more. The console is all electronic with a TFT display instead of mechanical instruments but the only significant difference this makes in driving is that when a turn indicator is used the console display shows a video feed for the blind-spot that matches the lane change direction. This is a significant safety feature and will reduce the incidence of collisions. But the capabilities of the hardware seem under utilised, hopefully they will release a software update at some future time to do more with it. The most significant benefit of the GV60 over the GV70 is that it has cameras instead of mirrors at the sides of the car. This reduces drag and also removes the need to adjust mirrors to match the height of the driver. Also for driver instruction the instructor and learner get to see the same view. A logical development of such cars is an expansion pack for instruction that has displays in the passenger seat to show the instructor the same instrument view as the driver sees. The minimum list driveaway price for the GV60 is $117,171.50 and for the GV70 it is $138,119.89 both of which are more than I m prepared to pay for a car. The GV60 apparently can be started by fingerprint which seems like a bad idea given the poor security of fingerprint sensors, but as regular car keys tend not to be too difficult to work around it probably doesn t matter. The Genesis web site makes it difficult to find the ranges of electric cars which is surprising. A Google search suggests that the GV60 can do 466Km and the GV70 can do 410Km which are both reasonable numbers and nothing to be ashamed of. The GV70 was a fun car to drive and the GV60 looks like it would be even better. I recommend that everyone who likes technology take one for a test drive, but for my own use I m looking for something that costs less than half as much.

[1] https://www.genesis.com/au/en/models/luxury-suv-genesis/gv60/highlights.html

Russell Coker: Considering Convergence

What is Convergence In 2013 Kyle Rankin (at the time Linux Journal columnist and CSO of Purism) wrote a Linux Journal article about Linux convergence [1] (which means using a phone and a dock to replace a desktop) featuring the Nokia N900 smart phone and a chroot environment on the Motorola Droid 4 Android phone. Both of them have very limited hardware even by the standards of the day and neither of which were systems I d consider using all the time. None of the Android phones I used at that time were at all comparable to any sort of desktop system I d want to use. Hardware for Convergence Comparing a Phone to a Laptop The first hardware issue for convergence is docks and other accessories to attach a small computer to hardware designed for larger computers. Laptop docks have been around for decades and for decades I haven t been using them because they have all been expensive and specific to a particular model of laptop. Having an expensive dock at home and an expensive dock at the office and then replacing them both when the laptop is replaced may work well for some people but wasn t something I wanted to do. The USB-C interface supports data, power, and DisplayPort video over the same cable and now USB-C docks start at about $20 on eBay and dock functionality is built in to many new monitors. I can take a USB-C device to the office of any large company and know there s a good chance that there will be a USB-C dock ready for me to use. The fact that USB-C is a standard feature for phones gives obvious potential for convergence. The next issue is performance. The Passmark benchmark seems like a reasonable way to compare CPUs [2]. It may not be the best benchmark but it has an excellent set of published results for Intel and AMD CPUs. I ran that benchmark on my Librem5 [3] and got a result of 507 for the CPU score. At the end of 2017 I got a Thinkpad X301 [4] which rates 678 on Passmark. So the Librem5 has 3/4 the CPU power of a laptop that was OK for my use in 2018. Given that the X301 was about the minimum specs for a PC that I can use (for things other than serious compiles, running VMs, etc) the Librem 5 has 3/4 the CPU power, only 3G of RAM compared to 6G, and 32G of storage compared to 64G. Here is the Passmark page for my Librem5 [5]. As an aside my Libnrem5 is apparently 25% faster than the other results for the same CPU did the Purism people do something to make their device faster than most? For me the Librem5 would be at the very low end of what I would consider a usable desktop system. A friend s N900 (like the one Kyle used) won t complete the Passmark test apparently due to the Extended Instructions (NEON) test failing. But of the rest of the tests most of them gave a result that was well below 10% of the result from the Librem5 and only the Compression and CPU Single Threaded tests managed to exceed 1/4 the speed of the Librem5. One thing to note when considering the specs of phones vs desktop systems is that the MicroSD cards designed for use in dashcams and other continuous recording devices have TBW ratings that compare well to SSDs designed for use in PCs, so swap to a MicroSD card should work reasonably well and be significantly faster than the hard disks I was using for swap in 2013! In 2013 I was using a Thinkpad T420 as my main system [6], it had 8G of RAM (the same as my current laptop) although I noted that 4G was slow but usable at the time. Basically it seems that the Librem5 was about the sort of hardware I could have used for convergence in 2013. But by today s standards and with the need to drive 4K monitors etc it s not that great. The N900 hardware specs seem very similar to the Thinkpads I was using from 1998 to about 2003. However a device for convergence will usually do more things than a laptop (IE phone and camera functionality) and software had become significantly more bloated in 1998 to 2013 time period. A Linux desktop system performed reasonably with 32MB of RAM in 1998 but by 2013 even 2G was limiting. Software Issues for Convergence Jeremiah Foster (Director PureOS at Purism) wrote an interesting overview of some of the software issues of convergence [7]. One of the most obvious is that the best app design for a small screen is often very different from that for a large screen. Phone apps usually have a single window that shows a view of only one part of the data that is being worked on (EG an email program that shows a list of messages or the contents of a single message but not both). Desktop apps of any complexity will either have support for multiple windows for different data (EG two messages displayed in different windows) or a single window with multiple different types of data (EG message list and a single message). What we ideally want is all the important apps to support changing modes when the active display is changed to one of a different size/resolution. The Purism people are doing some really good work in this regard. But it is a large project that needs to involve a huge range of apps. The next thing that needs to be addressed is the OS interface for managing apps and metadata. On a phone you swipe from one part of the screen to get a list of apps while on a desktop you will probably have a small section of a large monitor reserved for showing a window list. On a desktop you will typically have an app to manage a list of items copied to the clipboard while on Android and iOS there is AFAIK no standard way to do that (there is a selection of apps in the Google Play Store to do this sort of thing). Purism has a blog post by Sebastian Krzyszkowiak about some of the development of the OS to make it work better for convergence and the status of getting it in Debian [8]. The limitations in phone hardware force changes to the software. Software needs to use less memory because phone RAM can t be upgraded. The OS needs to be configured for low RAM use which includes technologies like the zram kernel memory compression feature. Security When mobile phones first came out they were used for less secret data. Loss of a phone was annoying and expensive but not a security problem. Now phone theft for the purpose of gaining access to resources stored on the phone is becoming a known crime, here is a news report about a thief stealing credit cards and phones to receive the SMS notifications from banks [9]. We should expect that trend to continue, stealing mobile devices for ssh keys, management tools for cloud services, etc is something we should expect to happen. A problem with mobile phones in current use is that they have one login used for all access from trivial things done in low security environments (EG paying for public transport) to sensitive things done in more secure environments (EG online banking and healthcare). Some applications take extra precautions for this EG the Android app I use for online banking requires authentication before performing any operations. The Samsung version of Android has a system called Knox for running a separate secured workspace [10]. I don t think that the Knox approach would work well for a full Linux desktop environment, but something that provides some similar features would be a really good idea. Also running apps in containers as much as possible would be a good security feature, this is done by default in Android and desktop OSs could benefit from it. The Linux desktop security model of logging in to a single account and getting access to everything has been outdated for a long time, probably ever since single-user Linux systems became popular. We need to change this for many reasons and convergence just makes it more urgent. Conclusion I have become convinced that convergence is the way of the future. It has the potential to make transporting computers easier, purchasing cheaper (buy just a phone and not buy desktop and laptop systems), and access to data more convenient. The Librem5 doesn t seem up to the task for my use due to being slow and having short battery life, the PinePhone Pro has more powerful hardware and allegedly has better battery life [11] so it might work for my needs. The PinePhone Pro probably won t meet the desktop computing needs of most people, but hardware keeps getting faster and cheaper so eventually most people could have their computing needs satisfied with a phone. The current state of software for convergence and for Linux desktop security needs some improvement. I have some experience with Linux security so this is something I can help work on. To work on improving this I asked Linux Australia for a grant for me and a friend to get PinePhone Pro devices and a selection of accessories to go with them. Having both a Librem5 and a PinePhone Pro means that I can test software in different configurations which will make developing software easier. Also having a friend who s working on similar things will help a lot, especially as he has some low level hardware skills that I lack. Linux Australia awarded the grant and now the PinePhones are in transit. Hopefully I will have a PinePhone in a couple of weeks to start work on this.

Russell Coker: Links April 2023

Cory Doctorow has an insightful article Gig Work is the Opposite of Steampunk [1] about the horrors that companies like Amazon are forcing on their employees. Valerie Aurora and Leigh Honeywell wrote an insightful article about the al Capone theory of sexual harassment [2]. Why people who sexually harass others usually perform other anti-social activity that is also easier to prosecute. The IEEE has an interesting article about using ML for parts of the CPU design process, both the technical issues and the controversy about competing ideas which is probably caused by sexism [3]. Love and taxes are forever my heart is a line from an anime dating sim game that prepares US taxes [4]. Unfortunately it was removed from Steam. The existence of the game is a weird social commentary and removing the game because you can t have an anime hottie do taxes is bizarre but also understandable given liability issues. There s no mention in the review of whether male hotties are available for people who prefer dating guys. As an aside my accountant looks like he is allergic to exercise The Killdozer Book web site (which has an invalid SSL certificate so you have to click on advanced in Chrome to get to the content) has an insightful article debunking some of the stories about the Killdozer [5]. He wasn t some sort of hero of freedom, he was just a jerk who reneged on a deal hoping to get more money, thought that laws shouldn t apply to him, and killed himself because of it. Apparently some big tech companies are knowingly hiring people to not work unlike the usual large corporate case of unknowingly hiring people to not work [6]. Silicon Valley is a good TV show, and it s apparently realistic. Ron Garrett wrote in insightful blog post about theoretical attacks on Bitcoin and how Bitcoin could be used [7]. The conclusion is not good for Bitcoin. Compiler Explorer is a program that shows how various C++ compilers produce assembly code for various architectures, this site hosts the main active instance [8]. There are other instances, here is an instance that produces code for the Ruzzian Elbrus architecture [9]. The Elbrus Wikipedia page is interesting [10]. Apparently the Ruzzians don t want this information to be spread, LOL. The Smithsonian Magazine has an interesting article about pet parrots being taught to video call each other [11]. Apparently parrots are social animals and can develop psychological problems if kept alone, so the video calls can be good for them. Also the owners had to monitor the chats to ensure that they played nicely together, just like play-dates for kids! Phoronix has an amusing article about the drama regarding the AMD Spectral Chicken bit in the Linux kernel source [12]. This page listing bad free software licenses is amusing [13]. The ACS has an interesting article about how Samsung fakes photos of the moon and presumably could fake other photos of notable objects that don t change [14]. The way that they proved the forgery was interesting.

[1] https://tinyurl.com/2fer3f5j
[2] https://tinyurl.com/2q4wgc26
[3] https://spectrum.ieee.org/chip-design-controversy
[4] https://tinyurl.com/2mslyfcv
[5] https://killdozerbook.com/2018/07/fake-news/
[6] https://tinyurl.com/25qtqyn4
[7] https://tinyurl.com/2dhq5qrx
[8] https://godbolt.org/
[9] https://ce.mentality.rip/
[10] https://en.wikipedia.org/wiki/Elbrus-8S
[11] https://tinyurl.com/2bktn42p
[12] https://tinyurl.com/24pqhlf6
[13] https://github.com/ErikMcClure/bad-licenses
[14] https://tinyurl.com/2eo65py7

Russell Coker: Write a blog post in the style of Russell Coker

Feeling a bit bored I asked ChatGPT Write a blog post in the style of Russell Coker and the result is in the section below. I don t know if ChatGPT knows that the person asking the question is the same as the person being asked about. If a human had created that I d be certain that great computer scientist and writer was an attempt at flattery, for a machine I m not sure. I have not written a single book, but I expect that in some alternate universe some version of me has written several. I don t know if humans would describe my writing as being known for clarity, precision, and depth . I would not be surprised if no-one else wrote about it so I guess I m forced to read what he wrote would be a more common response. The actual article part doesn t seem to be in my style at all. Firstly it s very short at only 312 words, while I have written some short posts most of them are much longer. To find this out I did some MySQL queries to get the lengths of posts (I used this blog post as inspiration [1]). Note that multiple sequential spaces counts as multiple words.

# get post ID and word count
SELECT id, LENGTH(post_content) - LENGTH(REPLACE(REPLACE(REPLACE(REPLACE(post_content, "\r", ""), "\n", ""), "\t", ""), " ", "")) + 1 AS wordcount FROM wp_posts where post_status = 'publish' and post_type='post';
# get average word count
SELECT avg(LENGTH(post_content) - LENGTH(REPLACE(REPLACE(REPLACE(REPLACE(post_content, "\r", ""), "\n", ""), "\t", ""), " ", "")) + 1) FROM wp_posts where post_status = 'publish' and post_type='post';
# get the first posts by length
SELECT id, LENGTH(post_content) - LENGTH(REPLACE(REPLACE(REPLACE(REPLACE(post_content, "\r", ""), "\n", ""), "\t", ""), " ", "")) + 1 AS wordcount, post_content FROM wp_posts where post_status = 'publish' and post_type='post' ORDER BY wordcount limit 10;
# get a count of the posts less than 312 words
SELECT count(*) from wp_posts where (LENGTH(post_content) - LENGTH(REPLACE(REPLACE(REPLACE(REPLACE(post_content, "\r", ""), "\n", ""), "\t", ""), " ", "")) + 1) < 312 and post_status = 'publish' and post_type='post';
# get a count of all posts
select count(*) from wp_posts where post_status = 'publish' and post_type='post';

It turns out that there are 333/1521 posts that are less than 312 words and the average length is 665 words. Of the shortest posts a large portion were written before Twitter became popular and had the sort of unimportant content that Twitter is good for. It seems ironic that ChatGPT says that I'm known for "depth" and then writes a short post allegedly in my style. As for the actual content of the "post", it's not something that I greatly disagree with but it's definitely not something I'd write. If some manager or marketing person wrote something like this and asked my opinion I'd probably suppress a sigh and say it's OK for it's target market. I think that free software is better in many ways and for many reasons and that separately from the issue of merit free software is important because of the ways that it is used. We could debate various issues related to the quality of free software vs proprietary software but even people who don't believe that free software is of high quality have to admit that software that runs most mobile phones and most web servers is important. As much as I dislike Windows most desktop PCs and laptops run it so I can't claim it to be unimportant. So my first disagreement with the content is the issue of importance vs quality. One thing that ChatGPT is known for is weak arguments that appear convincing. "This diversity often leads to better software, as bugs are found and fixed faster, and new features are added more quickly" could be opposed by "the payment for proprietary software often leads to better software, as bugs are found and fixed faster, and new features are added more quickly". I think that any case where "feature of option A gives this list of good results" can be rewritten as "feature of the opposite of option A gives the same list of good results" and be equally convincing is a poor argument. Also any argument that seems to rest on "free software is all written by hobbyists" is ignoring the demands of users who need things done on a non-hobby timeframe, the many profitable companies that develop and support free software, and the employment status of a large portion of my Facebook friends (many of whom are paid for ~2000 hours a year of free software development and many more of whom have paid free software development as part of their work supporting the use of free software). Really the entire blog post it wrote seems to me like something a human might write if their boss assigned them to write about the benefits of free software, and that they would then write a new article saying the exact opposite if their boss asked them to. Finally I prefer the term "free software" to "open source software". The difference doesn't seem important to some people, but any being that doesn't know the difference won't do well at impersonating me. ChatGPT Result Hello everyone, I'm ChatGPT, and today I'm going to try my best to write a blog post in the style of the great computer scientist and writer, Russell Coker. Russell Coker is a renowned software engineer and writer, who is best known for his contributions to the Linux community, especially the Debian project. He has authored several books and articles on topics ranging from security to software engineering, and his writing style is known for its clarity, precision, and depth. So, without further ado, let's dive into the topic of this blog post, which is the importance of open-source software. Open-source software is software whose source code is available for anyone to inspect, modify, and distribute. This means that anyone can use, study, and improve the software, without any restrictions or fees. Open-source software has been around for a long time, but it has become more prevalent and important in recent years, thanks to the rise of the internet and the digital economy. Open-source software has several benefits, both for individuals and for society as a whole. One of the most significant benefits is that it fosters innovation and collaboration. When software is open-source, it means that anyone can contribute to it, which leads to a diverse range of perspectives and ideas. This diversity often leads to better software, as bugs are found and fixed faster, and new features are added more quickly. Another benefit of open-source software is that it is often more secure than proprietary software. Because the source code is available for anyone to inspect, vulnerabilities and security flaws can be found and fixed faster. This means that open-source software is often more reliable and trustworthy than proprietary software, which may have hidden backdoors or vulnerabilities that can be exploited by attackers. Open-source software is also often more cost-effective than proprietary software. Because it is free to use and distribute, organizations can save money on licensing fees and other costs associated with proprietary software. This can be particularly important for non-profit organizations or small businesses that may not have the resources to invest in expensive software licenses. In conclusion, open-source software is an important part of the digital landscape, and its benefits are numerous. Whether you are a software developer, a business owner, or an individual user, open-source software has something to offer. So, the next time you are looking for software to use, consider open-source options, and help support the collaborative and innovative spirit of the open-source community.

[1] https://idiallo.com/blog/wordcount-in-mysql

Russell Coker: BTRFS Rebuild Time

In February I replaced a Dell T320 server with a HP Z640 workstation for a home server/workstation [1]. The T320 has 8*3.5 drive bays which I had used to put 3*4TB disks in a BTRFS RAID-10 array for 6TB of usable capacity. The Z640 has only 2*3.5 bays and 4*2.5 bays, so one option I could have taken was to buy a 4TB 2.5 SSD and keep the same 3*4TB array as before. Instead I chose to use an 8TB disk I had spare in an array with one of the original 4TB disks and some extra on NVMe devices (the system has 2*1TB NVMe devices which are used as a 380G RAID-1 for the root filesystem and the rest for the storage array). It s nice how BTRFS allows putting any storage you have in a RAID-10 configuration. Unfortunately it seems that I chose the wrong 4TB disk to use for this as it failed three days ago. It gave thousands of read and write errors and Linux decided that the drive no longer existed. I tried rebooting the system to get it in the BTRFS array again but it failed again and failed so quickly that it wasn t even possible to use the data on it as part of a RAID rebuild. So I removed that disk and put in one of the other 4TB disks. As the array is comprised of an 8TB disk and 3 other devices that don t add up to 8TB the layout is the 8TB disk having one copy of everything and the other devices having parts of it. So the rebuild process comprised of copying data from the 8TB disk to the 4TB disk. For a RAID array run in the manner of Linux software RAID the rebuild of a RAID-1 involves a linear copy of data which is the optimal case for hard disks, copying 4TB of data in that manner would have an average speed of a bit over 100MB/s and take about 11 hours. With BTRFS the source disk has to be updated for each block that is recreated so the process was bottlenecked on writing to the 8TB disk. It took 2 days 23 hours to complete. The process involved reading 3,478,031MB and writing 4,405,545MB. The system was live for the process and some cron jobs etc were writing to the array, but in the 12 hours since the rebuild completed the array has had 7,038MB written. So presumably during the rebuild time about 42G of actual data were written to the array and the other 4.3TB written to the 8TB disk were from the process of copying 3.5TB from it to another device. Iostat reported that there were 645.36 TPS for the duration of the rebuild which seems like a decent number for a hard drive, during the process iostat reported that the drive had 99%+ of IO capacity used for the duration. While waiting for this to complete I wrote a blog post about storage trends [2]. One thing I didn t mention in that post is that if you are the type of person who checks the rebuild process fifty times a day then that should be counted as part of the cost of using slow storage. If instead of an 8TB disk plus some SSD storage I had used 2*4TB disks and 1*4TB SSD as I had considered doing then instead of having 3.8TB on one device I would have had about 2.5TB and the reconstruct would have probably taken 2/3 of the time. If I had moved the array to 3*4TB SSDs then it would have taken a small fraction of the time. One thing to note is that I made a mistake in this operation by removing the failed device instead of doing a btrfs replace operation which can be significantly faster. If I had correctly done this then I would have written a blog post about the rebuild taking 2 days or something, the issues of hard drives being slow and me compulsively checking the progress would still apply.

Russell Coker: Storage Trends 2023

It s been 2 years since my last blog post about storage trends [1]. Minimum Storage <=2TB In 2021 I stated that as MSY had 2TB disks for $72 and 2TB SSD for $245 it was barely worth considering a 2TB disk and anything less than 2TB wasn t worth considering. Now for 2TB storage from MSY NVMe starts at $129, SATA SSD starts at $143, and hard disks start at $75. I guess that NVMe is slightly cheaper due to some combination of economies of scale for manufacture/sales and having less postage costs. It really doesn t make sense to consider hard disks for storing 2TB or less. For storage for a small system (PC or laptop) the cheapest storage device is $19 for a 128G SATA SSD. But it wouldn t make sense to buy that when you can get a 256G SATA SSD for $22 or a 240G NVMe device for $23, saving $3 on storage wouldn t make any sense. For 512G of storage the prices are $32 for NVMe and $33 for SATA SSD. For 1TB of storage the prices start at $68 for SATA SSD and $74 for NVMe. Probably for the vast majority of home users 1TB of SATA SSD or NVMe is the minimum storage capacity to consider, the $50 price difference isn t much when considering the entire price of a PC or laptop and anything less than 1TB will run out quickly with modern use. Larger Storage 4TB+ The price for 4TB of storage from MSY is NVMe starting at $349, SATA SSD starting at $369, and hard disks starting at $115. If you need 4TB of RAID-1 storage then it might be worth saving $470 and getting hard drives for a home user. For business use it wouldn t make sense. Some laptops have two NVMe sockets so 8TB of storage (or 4TB of RAID-1) in a laptop would be interesting. For 8TB of storage the MSY prices are SATA SSD for $739 and hard drives starting at $179. Probably hard drives are the best choice for most situations where there is a need to store 8TB or more of data. But the prices are low enough to make 8TB SSD something that can be considered for home use, it doesn t seem that long ago that the 4TB hard drives I bought for my home server were almost that expensive. Big Storage MSY doesn t have 8TB NVMe, such devices are on eBay for $1700 for regular M.2 NVMe and just under $1000 for U.2 (server hot-swap devices). So if you need more than 8TB of NVMe storage then probably buying a server with U.2 built in is the correct solution. For home users who need more than 8TB of storage hard drives are a good solution. One issue is that the more affordable and larger drives use Shingled Magnetic Recording (SMR) which has some different performance characteristics for certain workloads. Apparently SMR performs badly for anything other than large file storage. Why MSY? I primarily used MSY prices for this post because they are a reliable local store that has a list of prices that is easy to read. For everything in this post I can get better prices by using eBay, the StaticIce.com.au price comparison site [2], and the computing section of the OzBargain site that gamifies finding good prices [3]. But a good shopping strategy nowadays is to compare prices in a store to determine what items are in your price range and then shop around for price on the item you want. Checking all the different bargain sites for all these items would take much more time than I want to spend writing a blog post! Conclusion Hard drives don t make sense for the vast majority of systems. Not for laptops, not for typical desktop PCs, and not for small business servers (say 8TB or less of RAID storage). Hard drives only make sense for dozens or hundreds of TB of storage and even then finding out how to deal with SMR issues is going to increase the pain of deployment. Maybe using a combination of SSD and hard drives to deal with the SMR issues is going to be a competitive advantage for NAS vendors in future. NVMe looks like it s on the way to being cheaper than SATA SSD. There is likely to be a good market for systems with NVMe as the only internal storage option. The long term trend of systems without DVD drives and with maybe 2.5 SATA devices but no 3.5 SATA devices seems to lead to the GPU being the major part that needs to fit into a PC case that determines the overall size. Maybe there will be a new trend of GPUs connected to riser cards so they can be parallel to the motherboard for compact PCs. For business desktop systems (IE low powered graphics hardware as it s not for gaming) I expect that the trend will be towards NUC type devices which are already based around the M.2 as a storage device size.

Russell Coker: Links March 2023

Interesting paper about a plan for eugenics in dogs with an aim to get human equivalent IQ within 100 generations [1]. It gets a bit silly when the author predicts IQs of 8000+ as there will eventually be limits of what can fit in one head. But the basic concept is good. Interesting article about what happens inside a proton [2]. This makes some aspects of the Trisolar series and the Dragon s Egg series seem less implausible. Insightful article about how crypto-currencies really work [3]. Basically the vast majority of users trust some company that s outside the scope of most financial regulations to act as their bank. Surprisingly the author doesn t seem to identify such things as a Ponzi scheme. Bruce Schneier wrote an interesting blog post about AIs as hackers [4]. Cory Doctorow wrote an insightful article titled The Enshittification of TikTok which is about the enshittification of commercial Internet platforms in general [5]. We need more regulation of such things. Cat Valente wrote an insightful article titled Stop Talking to Each Other and Start Buying Things: Three Decades of Survival in the Desert of Social Media about the desire to profit from social media repeatedly destroying platforms [6]. This Onion video has a good point, I don t want to watch videos on news sites etc [7]. We need ad-blockers that can block video on all sites other than YouTube etc. Wired has an interesting article about the machines that still need floppy disks, including early versions of the 747 [8]. There are devices to convert the floppy drive interface to a USB storage device which are being used on some systems but which presumably aren t certified for a 747. The article says that 3.5 disks cost $1 each because they are rare that s still cheaper than when they were first released. Android Police has an interesting article about un-redacting information in PNG files [9]. It seems that some software on Pixel devices hasn t been truncating files when editing them, just writing the new data over top and some platforms (notably Discord) send the entire file wuthout parsing it (unlike Twitter for example which removes EXIF data to protect users). Then even though a PNG file is compressed from the later part of the data someone can deduce the earlier data. Teen Vogue has an insightful article about the harm that influencer parents do to their children [10]. Jonathan McDowell wrote a very informative blog post about his new RISC-V computer running Debian [11]. He says that it takes 10 hours to do a full Debian kernel build (compared to 14 minutes for my 18 core E5-2696) so it s about 2% the CPU speed of a high end 2015 server CPU which is pretty good for an embedded devivce. That is similar to some of the low end Thinkpads that were on sale in 2015. The Surviving Tomorrow site has an interesting article about a community where all property is community owned [12]. It s an extremist Christian group and the article is written by a slightly different Christian extremist, but the organisation is interesting. A technology positive atheist versions of this would be good. Bruce Schneier and Nathan E. Sanders co-wrote an insightful article about how AI could exploit the process of making laws [13]. We really need to crack down on political lobbying, any time a constitution is being amender prohibiting lobbying should be included. Anarcat wrote a very informative blog post about the Framework laptops that are designed to be upgraded by the user [14]. The motherboard can be replaced and there are cases designed so you can use the old laptop motherboard as an embedded PC. Before 2017 I would have been very interested in such a laptop. Now I ve moved to low power laptops and servers for serious compiles and a second-hand Thinkpad X1 Carbon costs less than a new Framework motherboard. But this will be a really good product for people with more demanding needs than mine. Pity they don t have a keyboard with the Thinkpad Trackpoint.

Russell Coker: Strange X11 Grabbing

A couple of days ago I upgraded my home server from Debian/Bullseye to Debian/Testing (soon to be Bookworm). Since then KDE sessions on that system have had problems of locking the input queue, the mouse can move and mouse-over events work but clicking the mouse or pressing the keyboard does nothing. Various web pages suggested that the xdotool program (in the xdotool package in Debian) can address this. The problem is apparently programs grabbing the input and not letting it go. The command xdotool key XF86LogGrabInfo causes the xorg server to dump information on it s grabs . After running that command I looked in /var/log/Xorg.0.log and found that active grabs were only held by /usr/bin/kwin_x11 and /usr/bin/kglobalaccel5. So it seems like a KDE issue. Other systems running X11 with Debian/Testing (such as the laptop I m using to write this blog post) don t have the problem, so it could be something related to the KDE configuration of the account used on that system. The command xdotool key XF86Ungrab is supposed to break out of such a grab, but for me didn t do so. On the same system running KDE with Wayland works fine in this regard. Does Wayland do things differently and not allow this grabbing to block everything? Does KDE have an X11 specific bug? Is there a race condition that just gets triggered by the speed of Xorg on that system but not by the slightly different timings of Wayland? I might never find out. I previously wrote about problems with Wayland/KDE on laptops [1]. Fortunately this bug happened to occur on a server so inability to reconfigure monitors isn t necessarily a deal breaker, although being unable to use some of the high-DPI settings for the 4K monitor it has may be an issue. It will be really annoying if some of the laptop configurations I support get this grabbing problem. But since that time I have learned of the kscreen-doctor command which is included in Debian/Testing and can do some of the necessary things, it doesn t have a man page so you have to run kscreen-doctor -h for documentation.

[1] https://etbe.coker.com.au/2023/02/05/wayland-bookworm/

B lint R czey: Building the Linux kernel in under 10 seconds with Firebuild

Russell published an interesting post about his first experience with Firebuild accelerating refpolicy s and the Linux kernel s build. It turned out a few small tweaks could accelerate the builds even more, crossing the 10 second barrier with Linux s build.

Build performance with 18 cores The Linux kernel s build time is a widely used benchmark for compilers, making it a prime candidate to test a build accelerator as well. In the first run on Russell s 18 core test system the observed user+sys CPU time was cut by 44% with an actual increase in wall clock time which was quite unusual. Firebuild performed much better than that in prior tests. To replicate the results I ve set up a clean Debian Bookworm VM on my machine:

lxc launch images:debian/bookworm  vm -c limits.cpu=18 -c limits.memory=16GB bookworm-vm

Compiling Linux 6.1.10 in this clean Debian VM showed build times closer to what I expected to see, ~72% less wall clock time and ~97% less user+sys CPU time:

$ make defconfig && time make bzImage -j18
real	1m31.157s
user	20m54.256s
sys	2m25.986s
$ make defconfig && time firebuild make bzImage -j18
# first run:
real	2m3.948s
user	21m28.845s
sys	4m16.526s
# second run
real	0m25.783s
user	0m56.618s
sys	0m21.622s

There are multiple differences between Russell s and my test system including having different CPUs (E5-2696v3 vs. virtualized Ryzen 5900X) and different file systems (BTRFS RAID-1 vs ext4), but I don t think those could explain the observed mismatch in performance. The difference may be worth further analysis, but let s get back to squeezing out more performance from Firebuild. Firebuild was developed on Ubuntu. I was wondering if Firebuild was faster there, but I got only slightly better build times in an identical VM running Ubuntu 22.10 (Kinetic Kudu):

$ make defconfig && time make bzImage -j18
real	1m31.130s
user	20m52.930s
sys	2m12.294s
$ make defconfig && time firebuild make bzImage -j18
# first run:
real	2m3.274s
user	21m18.810s
sys	3m45.351s
# second run
real	0m25.532s
user	0m53.087s
sys	0m18.578s

The KVM virtualization certainly introduces an overhead, thus builds must be faster in LXC containers. Indeed, all builds are faster by a few percents:

$ lxc launch ubuntu:kinetic kinetic-container
...
$ make defconfig && time make bzImage -j18
real	1m27.462s
user	20m25.190s
sys	2m13.014s
$ make defconfig && time firebuild make bzImage -j18
# first run:
real	1m53.253s
user	21m42.730s
sys	3m41.067s
# second run
real	0m24.702s
user	0m49.120s
sys	0m16.840s
# Cache size:    1.85 GB

Apparently this ~72% reduction in wall clock time is what one should expect by simply prefixing the build command with firebuild on a similar configuration, but we should not stop here. Firebuild does not accelerate quicker commands by default to save cache space. This howto suggests letting firebuild accelerate all commands including even "sh by passing "-o 'processes.skip_cache = []' to firebuild.

Accelerating all commands in this build s case increases cache size by only 9%, and increases the wall clock time saving to 91%, not only making the build more than 10X faster, but finishing it in less than 8 seconds, which may be a new world record!:

$ make defconfig && time firebuild -o 'processes.skip_cache = []' make bzImage -j18
# first run:
real	1m54.937s
user	21m35.988s
sys	3m42.335s
# second run
real	0m7.861s
user	0m15.332s
sys	0m7.707s
# Cache size:    2.02 GB

There are even faster CPUs on the market than this 5900X. If you happen to have access to one please leave a comment if you could go below 5 seconds! Scaling to higher core counts and comparison with ccache Russell raised the very valid point about Firebuild s single threaded supervisor being a bottleneck on high core systems and comparison to ccache also came up in comments. Since ccache does not have a central supervisor it could scale better with more cores, but let s see if ccache could go below 10 seconds with the build times

Well, no. The best time time for ccache is 18.81s, with -j24. Both firebuild and ccache keep gaining from extra cores up to 8 cores, but beyond that the wall clock time improvements diminish. The more interesting difference is that firebuild s user and sys time is basically constant from -j1 to -j24 similarly to ccache s user time, but ccache s sys time increases linearly or exponentially with the number of used cores. I suspect this is due to the many parallel ccache processes performing file operations to check if cache entries could be reused, while in firebuild s case the supervisor performs most of that work not requiring in-kernel synchronization across multiple cores. It is true, that the single threaded firebuild supervisor is a bottleneck, but the supervisor also implements a central filesystem cache, thus checking if a command s cache entry can be reused can be implemented with much fewer system calls and much less user space hashing making the architecture more efficient overall than ccache s. The beauty of Firebuild is not being faster than ccache, but being faster than ccache with basically no hard-coded information about how C compilers work. It can accelerate any other compiler or program that generates deterministic output from its input, just by observing what they did in their prior runs. It is like having ccache for every compiler including in-house developed ones, and also for random slow scripts.

Russell Coker: Firebuild

After reading B lint s blog post about Firebuild (a compile cache) [1] I decided to give it a go. It s non-free, the project web site [2] says that it s free for non-commercial use or commercial trials. My first attempt at building a Debian package failed due to man-recode using a seccomp() sandbox, I filed Debian bug #1032619 [3] about this (thanks for the quick response B lint). The solution for me was to edit /etc/firebuild.conf and add man-recode to the dont_intercept list. The new version that s just been uploaded to Debian fixes it by disabling seccomp() and will presumably allow slightly better performance. Here are the results of building the refpolicy package with Firebuild, a regular build, the first build with Firebuild (30% slower) and a rebuild with Firebuild that reduced the time by almost 42%.

real    1m32.026s
user    4m20.200s
sys     2m33.324s
real    2m4.111s
user    6m31.769s
sys     3m53.681s
real    0m53.632s
user    1m41.334s
sys     3m36.227s

Next I did a test of building a Linux 6.1.10 kernel with make bzImage -j18 , here are the results from a normal build, first build with firebuild, and second build. The real time is worse with firebuild for this on my machine. I think that the relative speeds of my CPU (reasonably fast 18 core) and storage (two of the slower NVMe devices in a BTRFS RAID-1) is the cause of the first build being relatively so much slower for make bzImage than for building the refpolicy, as the kernel build process involves a lot more data. For the final build I moved ~/.cache/firebuild to a tmpfs (I have 128G of RAM and not much running on my machine at the time of the tests), even then building with firebuild was slightly slower in real time but took significantly less CPU time (user+real being 20mins instead of 36m). I also ran several tests with the kernel source tree on a tmpfs but for unknown reasons those tests each took about 6 minutes. Does firebuild or the Linux kernel build process dislike tmpfs for some reason?

real    2m43.020s
user    31m30.551s
sys     5m15.279s
real    8m49.675s
user    64m11.258s
sys     19m39.016s
real    3m6.858s
user    7m47.556s
sys     9m22.513s
real    2m51.910s
user    10m53.870s
sys     9m21.307s

One thing I noticed from the kernel build tests is that the total CPU time taken by the firebuild process (as reported by ps) was more than 2/3 of the run time and top usually reported it as taking around 75% of a CPU core. It seems to me that the firebuild process itself is a bottleneck on build speed. Building refpolicy without firebuild has an average of 4.5 cores in use while building the kernel haas 13.5. Unless they make a multi-threaded version of firebuild it seems that it won t give the performance one would hope for from a CPU with 18+ cores. I presume that if I had been running with hyper-threading enabled then firebuild would have been even worse for kernel builds as it would sometimes get on the second thread of a core. It looks like firebuild would perform better on AMD CPUs as they tend to have fewer CPU cores with greater average performance per core so a single CPU core for firebuild will be less limited. I presume that the firebuild developers will make it perform better with large numbers of cores in future, the latest Intel laptop CPUs have 16+ cores and servers with 2*40core CPUs are common. The performance improvement for refpolicy is significant as a portion of build time, but insignificant in terms of real time. A full build of refpolicy doesn t take enough time to get a Coke and reducing it doesn t offer a huge benefit, if Firebuild was available in past years when refpolicy took 20 minutes to build (when DDR2 was the best RAM available) then it would be a different story. There is some potential to optimise the build of refpolicy for the non-firebuild case. Getting it to average more than 4.5 cores in use when there s 18 available should be possible, there are a number of shell for loops in the main Makefile and maybe some of them can be replaced by make constructs to allow running in parallel. If it used 7 cores on average then it would be faster in a regular build than it currently is with firebuild and a hot cache. Any advice from make experts would be appreciated.