I've lost track with, but IIRC, someone wrote here, or other ML, or even forums, kern.sched.preempt_thresh=224 was the default for PC-BSD.
And found some discussion started at [1] on freebsd-stable ML in Apr. 2018. One more place is at forums [2]. Sorry, not read all of them to confirm. [1] https://lists.freebsd.org/pipermail/freebsd-stable/2018-April/088678.html [2] https://forums.freebsd.org/threads/general-freebsd-desktop-workload-optimization-thread.21853/ On Sat, 19 Nov 2022 10:28:50 +0100 Hans Petter Selasky <h...@selasky.org> wrote: > Hi Alexander, > > Thank you for the pointers. > > I will try it out. > > --HPS > > On 11/18/22 09:18, Alexander Leidinger wrote: > > Quoting Hans Petter Selasky <h...@selasky.org> (from Fri, 18 Nov 2022 > > 05:47:58 +0100): > > > >> Hi, > >> > >> I'm doing some work with audio and have noticed some problems with the > >> ULE scheduler. I have a program that generate audio based on > >> key-presses. When no keys are pressed, the load is near 0%, but as > >> soon as you start pressing keys, the load goes maybe to 80% of a CPU > >> core. This program I run with rtprio 8 xxx. The issue I observe or > >> hear actually, is that it takes too long until the scheduler grasps > >> that this program needs it's own CPU core and stops time-sharing the > >> program. When I however use cpuset -l xxx rtprio 8 yyy everything is > >> good, and the program outputs realtime audio in-time. > > > > I have something in my mind about ULE not handling idleprio and/or > > rtprio correctly, but I have no pointer to a validation of this. > > > >> Or is this perhaps a CPU frequency stepping issue? > > > > You could play with > > rc.conf (/etc/rc.d/power_profile): > > performance_cpu_freq="HIGH" > > performance_cx_lowest="C3" # see sysctl hw.cpu.0 | grep cx > > economy_cx_lowest="C3" # see sysctl hw.cpu.0 | grep cx > > > > Your system may provide other Cx possibilities, and ging to a lower > > number (e.g. C1) means less power-saving but faster response from the > > CPU (I do not expect that this is causing the issue you have). > > > >> Any advice on where to look? > > > > Potential sysctl to play with to change "interactivity detection" in ULE: > > https://www.mail-archive.com/freebsd-stable@freebsd.org/msg112118.html > > > > Bye, > > Alexander. > > > -- Tomoaki AOKI <junch...@dec.sakura.ne.jp>
