On 2023-05-01 22:24, Nikos Chantziaras wrote:
On 26/04/2023 23:06, Holger Hoffstätte wrote:
On 2023-04-26 18:15, Nikos Chantziaras wrote:
So I wanted to try the BMQ scheduler in gentoo-sources. Is just
enabling it in the kernel build all that's needed? I did so,
booted, and:
$ dmesg | grep -i bmq [ 0.100284] sched/bmq: BMQ CPU Scheduler
v6.1-r4 by Alfred Chen.
That's all and it's in use now? Or do I need to toggle anything
else?
That's all you need to do, right. You can slso alternatively switch
to PDS under the "General setup > Scheduler features" kernel-config
menu, which is slightly better for throughput and "more correct"
when many tasks have varying priorities - beefy workstation or
server. BMQ is kind of simplistic (in an elegant way), but that's
why it is so effective for low-end systems and desktops. Run iperf3
over loopback (i.e. both server and client) to see the difference.
Switched back to the default (called "CFS" I think.)
BMQ has severe issues. When emerging something while I play a game
(either native or through wine-proton,) there's long lag spikes and
freezes. Even worse, there's bugs like the system completely hanging
on shutdown, or "umount" hanging with 100% CPU use by two kernel
threads.
Can you try booting with psi=0 and check if that helps? There's a known
bad interaction with the PSI (Pressure Stall Information) mechanism,
which is active by default in many kernel configs. The latest version
of the BMQ patch makes sure to turn it off, you may not have that version
yet. BMQ (and PDS) works fine and has done so for quite a while.
-h
