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| wiki:system_configuration [2017/05/30 19:03] – autostatic | wiki:system_configuration [2020/03/17 21:21] – [The kernel] autostatic |
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| Run ''uname -a'' to find out which kernel you're running: | Run ''uname -a'' to find out which kernel you're running: |
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| Linux xps13 4.8.15-core2-rt10 #1 SMP PREEMPT RT Sun May 28 10:43:44 CEST 2017 x86_64 x86_64 x86_64 GNU/Linux | Linux XPS-13-9360 5.4.24-core2-rt15 #1~bionic1 SMP PREEMPT_RT Tue Mar 17 18:00:29 CET 2020 x86_64 x86_64 x86_64 GNU/Linux |
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| 4.8.15-core2-rt10 is the version number of the currently running kernel. The configuration file with which this kernel was created can be found in ''/boot/config-4.8.15-core2-rt10''. Open it, and check if it has the following characteristics: | 5.4.24-core2-rt15 is the version number of the currently running kernel. The configuration file with which this kernel was created can be found in ''/boot/config-5.4.24-core2-rt15''. Open it, and check if it has the following characteristics: |
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| CONFIG_HZ_1000=y | CONFIG_HZ_1000=y |
| == Debian == | == Debian == |
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| Since Debian Wheezy an RT variant is also available in the [[https://packages.debian.org/search?suite=default§ion=all&arch=any&searchon=names&keywords=linux-image-rt|stock repositories]]; unfortunately its system timer is set to 250 Hz instead of 1000 Hz, so you'll probably want to recompile your own kernel anyway, especially if you use ALSA MIDI. These kernels incorporate [[http://pengutronix.de/software/linux-rt/debian_en.html|Pengutronix]] patches (see [[https://wiki.debian.org/DebianMultimedia#Realtime_kernel|DebianMultimedia Wiki]]). The [[http://www.64studio.com/|64 Studio]] real-time kernels are in the backports apt repository, so for Debian Squeeze you will have to add the following line to your apt sources list: | Since Debian Wheezy an RT variant is also available in the [[https://packages.debian.org/search?suite=default§ion=all&arch=any&searchon=names&keywords=linux-image-rt|stock repositories]]; unfortunately its system timer is set to 250 Hz instead of 1000 Hz, so you'll probably want to recompile your own kernel anyway, especially if you use ALSA MIDI. These kernels incorporate [[http://pengutronix.de/software/linux-rt/debian_en.html|Pengutronix]] patches (see [[https://wiki.debian.org/DebianMultimedia#Realtime_kernel|DebianMultimedia Wiki]]). |
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| deb http://apt.64studio.com/backports squeeze-backports main | |
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| == Arch == | == Arch == |
| == Gentoo == | == Gentoo == |
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| RT kernels are vailable in the pro-audio overlay (http://proaudio.tuxfamily.org/wiki/index.php?title=Main_Page). | AN audio overlay can be found here [[https://github.com/gentoo-audio/audio-overlay]]. |
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| === Build your own real-time kernel === | === Build your own real-time kernel === |
| sudo apt-get install kernel-package fakeroot build-essential | sudo apt-get install kernel-package fakeroot build-essential |
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| Download the kernel sources and the RT patchset (this example uses the 3.18 branch, you're free to use another kernel branch for which there is a RT patch set available): | Download the kernel sources and the RT patchset (this example uses the 4.8 branch, you're free to use another kernel branch for which there is a RT patch set available): |
| mkdir -p ~/tmp/linux-rt | mkdir -p ~/tmp/linux-rt |
| cd ~/tmp/linux-rt | cd ~/tmp/linux-rt |
| === DBus-controlled services === | === DBus-controlled services === |
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| DBus is a solid standard used for a wide variety of services which need to be started automatically, but on demand only, in the background, not specifically at boot. One set of DBus services used extensively in Ubuntu is 'gvfs', the virtual filesystem for the Gnome desktop; if these are permitted to run, polling of hardware including the USB bus will occur, which is likely to interfere with USB MIDI interfaces, eat CPU power, and cause xruns in general. To disable gvfs, become root and run the follwing two commands: | DBus is a solid standard used for a wide variety of services which need to be started automatically, but on demand only, in the background, not specifically at boot. One set of DBus services used extensively in Ubuntu is 'gvfs', the virtual filesystem for the Gnome desktop; if these are permitted to run, polling of hardware including the USB bus will occur, which is likely to interfere with USB MIDI interfaces, eat CPU power, and cause xruns in general. To disable gvfs, become root and run the following two commands: |
| mv /usr/share/dbus-1/servicesgvfs-daemon.service /usr/share/dbus-1/servicesgvfs-daemon.service.disabled | mv /usr/share/dbus-1/servicesgvfs-daemon.service /usr/share/dbus-1/servicesgvfs-daemon.service.disabled |
| mv /usr/share/dbus-1/services/gvfs-metadata.service /usr/share/dbus-1/servicesgvfs-metadata.service.disabled | mv /usr/share/dbus-1/services/gvfs-metadata.service /usr/share/dbus-1/servicesgvfs-metadata.service.disabled |
