August 2018 - Arch-proaudio - lists.archlinux.org

[arch-proaudio] Changes to jack/jack2 and realtime privileges
by David Runge 22 Aug '18

22 Aug '18

Hi all, as announced before [1], recent changes to the jack and jack2{,-dbus} packages (now in [extra] and [community] respectively) have made the previously shipped configurations obsolete and decoupled the audio group from acquiring realtime privileges by default when installing jack. The package realtime-privileges [2] has been created to serve as the new way of achieving this by the means of a dedicated 'realtime' group, to which users, that need the settings, must be added. It is now an optional dependency to jack and jack2{,-dbus} and can of course also be dependend upon from other packages if needed. In theory, this change shouldn't mean much of a difference to users, that need realtime (just install realtime-priviliges and add your user to the realtime group: `gpasswd -a <user> realtime`), while it doesn't have any consequences for users that have no use for it to begin with. Best, David [1] https://lists.archlinux.org/pipermail/arch-proaudio/2018-July/000163.html [2] https://www.archlinux.org/packages/community/any/realtime-privileges/ -- https://sleepmap.de

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[arch-proaudio] Linux RT BFQ kernel and frequency scaling
by Jeanette C. 02 Aug '18

02 Aug '18

Hey hey, when running the linux-rt-bfq kernel is it still possible to set/scale the frequency of a cpu like this: cpupower -c all frequency-set -g schedutil and back using the "performance" model or similar? Best wishes, Jeanette -------- * Website: http://juliencoder.de - for summer is a state of sound * SoundCloud: https://soundcloud.com/jeanette_c * Youtube: https://www.youtube.com/channel/UCMS4rfGrTwz8W7jhC1Jnv7g * GitHub: https://github.com/jeanette-c * Twitter: https://twitter.com/jeanette_c_s Don't, don't let me be the last to know Don't hold back, just let it go <3 (Britney Spears)

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[arch-proaudio] 'proaudio-settings' package
by bill-auger 01 Aug '18

01 Aug '18

aside from the new 'realtime' package, i would like to propose an audio-specific optimizations package of the sort that other av-centric distros commonly have - a package that contains goodies such as the 'realTimeConfigQuickScan' and 'rtirq' scripts that will inform the user how best to optimize their hardware IRQ and PCI latency and such; and other suggestions from the linuxaudio wiki[1] that can be automated, such as selectively disabling and re-enabling unnecessary services (screensaver, printing, *ehem* pulse), a .jackdrc with smaller buffers than the default config, etc i did a side-by-side comparison with the analogous proaudio-settings optimization packages from each of parabola, kxstudio, and ubuntustudio - they are all nearly identical in what they accomplish; but AFAIK currently arch does not have an analogous package - here are some examples of what they do: -------- using 'parabola-proaudio-settings'[2] as a reference: # custom kernel parameters to sysctl.d folder /etc/sysctl.d/99-sysctl.conf # By default, swap frequency defined by "swappiness" is set to 60. By reducing this number to 10, the system will wait much longer before trying to write to disk vm.swappiness = 10 # inotify watches for changes to files and reports them to applications requesting this information. When working with lots of audio data, a lot of watches will need to be kept track of, so they will need to be increased. fs.inotify.max_user_watches = 524288 -------- # ensure the ALSA MIDI driver is loaded /etc/modules-load.d//alsamidi.conf # If you want to use any MIDI hardware you need to ensure the ALSA MIDI driver is loaded snd_seq_midi -------- # recommended initial settings for jack /etc/jackdrc /usr/bin/jackd -P89 -t2000 -dalsa -dhw:0 -r44100 -p256 -n2 -Xseq -------- # systemd service # increase the highest requested RTC interrupt frequency (default is 64 Hz) /etc/systemd/system/parabola-proaudio-settings.service /etc/parabola-proaudio-settings.sh #!/bin/sh echo 2048 > /sys/class/rtc/rtc0/max_user_freq echo 2048 > /proc/sys/dev/hpet/max-user-freq cpupower frequency-set -g performance echo noop > /sys/block/sda/queue/scheduler -------- # extra virtual midi ports /etc/modprobe.d/snd-seq-dummy_16.conf #Creates extra virtual midi ports options snd-seq-dummy ports=8 -------- kxstudio 'kxstudio-default-settings'[3] has the following also: /etc/sysctl.d/10-kxstudio-sysctl-rules.conf dev.hpet.max-user-freq = 2048 -------- ubuntustudio 'ubuntustudio-default-settings'[4] suggests that 3072 is a better value for dev.hpet.max-user-freq (although they have it commented out) #dev.hpet.max-user-freq=3072 -------- both kxstudio and ubuntustudio have the following also (this is the only concern that is specified in the new 'realtime' package): /lib/udev/rules.d/99-kxstudio-udev.rules /lib/udev/rules.d/40-timer-permissions.rules KERNEL=="rtc0", GROUP="audio" KERNEL=="hpet", GROUP="audio" -------- [1]: https://wiki.linuxaudio.org/wiki/system_configuration [2]: https://git.parabola.nu/abslibre.git/tree/pcr/parabola-proaudio-settings?id… [3]: https://github.com/KXStudio/KXStudio/tree/master/default-settings [4]: https://git.launchpad.net/ubuntustudio-default-settings/tree/

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