| Both sides previous revisionPrevious revisionNext revision | Previous revisionNext revisionBoth sides next revision |
| wiki:system_configuration [2017/05/29 17:03] – [Filesystems] autostatic | wiki:system_configuration [2017/05/30 19:03] – autostatic |
|---|
| === Note about kernels === | === Note about kernels === |
| |
| * Kernels >= 2.6.31 seem to work pretty good without RT patch, also for real-time pro audio usage. It's not strictly necessary anymore to install a real-time ('rt') kernel to get good results. Although the best results are still expected when using a real-time kernel. Try it, test it and decide for yourself. | * Kernels >= 2.6.31 seem to work pretty well without RT patch, also for real-time pro audio usage. It's not strictly necessary anymore to install a real-time ('rt') kernel to get good results. Although the best results are still expected when using a real-time kernel. Try it, test it and decide for yourself. |
| * In the pre-2.6.39 kernel era rt kernels were indeed necessary in some cases where sound devices were sharing IRQ's with other peripherals. With the rt kernel and the rtirq script you could prioritize IRQ threads but since 2.6.39 it is possible to use the rtirq kernel with a generic kernel and the ''threadirqs'' kernel option. | * In the pre-2.6.39 kernel era rt kernels were indeed necessary in some cases where sound devices were sharing IRQ's with other peripherals. With the rt kernel and the rtirq script you could prioritize IRQ threads but since 2.6.39 it is possible to use the rtirq kernel with a generic kernel and the ''threadirqs'' kernel option. |
| * Many distro kernels, and many third-party-provided real-time kernels, are configured without the 1000 Hz setting. This is not significant for recording, but it can be an issue for live MIDI work if the application you're using does not rely on the ''snd-hrtimer'' kernel module. If your application is live MIDI, using ALSA MIDI and relies on ''/dev/rtc'' (so it doesn't rely on the ''snd-hrtimer'' kernel module), you may well want real-time, but you certainly need 1000 Hz. | * Many distro kernels, and many third-party-provided real-time kernels, are configured without the 1000 Hz setting. This is not significant for recording, but it can be an issue for live MIDI work if the application you're using does not rely on the ''snd-hrtimer'' kernel module. If your application is live MIDI, using ALSA MIDI and relies on ''/dev/rtc'' (so it doesn't rely on the ''snd-hrtimer'' kernel module), you may well want real-time, but you certainly need 1000 Hz. |
| recovery.//"((http://elinux.org/images/b/b6/EMMC-SSD_File_System_Tuning_Methodology_v1.0.pdf)) | recovery.//"((http://elinux.org/images/b/b6/EMMC-SSD_File_System_Tuning_Methodology_v1.0.pdf)) |
| |
| You can't use this parameter in ''/etc/fstab'' for the root partition, you will have to set it as a kernel parameter. So when using Grub you can add the following parameter to the ''GRUB_CMDLINE_LINUX_DEFAULT'' line in ''/etc/default/grub'': | You can't use this parameter in ''/etc/fstab'' for the root partition, you will have to set it as a kernel parameter. So when using Grub you can add the following parameter to the ''GRUB_CMDLINE_LINUX'' line in ''/etc/default/grub'': |
| rootflags=data=writeback | rootflags=data=writeback |
| | |
| @audio - memlock unlimited # maximum locked-in-memory address space (KB) | @audio - memlock unlimited # maximum locked-in-memory address space (KB) |
| |
| Setting ''memlock'' to ''unlimited'' shouldn't be strictly necessary since most apps would work fine with lower values (such as ''500000'').\\ | Setting ''memlock'' to ''unlimited'' shouldn't be strictly necessary since most apps would work fine with lower values (such as ''500000''). However, certain applications have been reported to complain or even to crash with lower values than ''unlimited''. On the other hand, giving unlimited capability of locking memory can cause buggy applications to temporarily freeze the whole system. See http://www.linuxmusicians.com/viewtopic.php?f=10&t=2193 for more details. |
| However, certain applications have been reported to complain or even to crash with lower values than ''unlimited''.\\ | |
| On the other hand, giving unlimited capability of locking memory can cause buggy applications to temporarily freeze the whole system.\\ | |
| See http://www.linuxmusicians.com/viewtopic.php?f=10&t=2193 for more details. | |
| |
| You could also allow the audio group to renice processes with the help of the ''limits.conf'' file, but since nice uses SCHED_OTHER it basically does nothing to increase the performance of a low-latency real-time audio environment that relies on SCHED_FIFO/SCHED_RR. Consult the //sched_setscheduler// manpage for more info on this subject. | You could also allow the audio group to renice processes with the help of the ''limits.conf'' file, but since nice uses SCHED_OTHER it basically does nothing to increase the performance of a low-latency real-time audio environment that relies on SCHED_FIFO/SCHED_RR. Consult the //sched_setscheduler// manpage for more info on this subject. |
