On Fri, 2025-08-08 at 07:29 +0200, Nam Cao wrote: > Gabriele Monaco <gmon...@redhat.com> writes: > > The monitor shows a violation also in case of priority inversion > > boosting, e.g.: > > > > stress-ng --prio-inv 2 > > This looks like something that would trigger the fair deadline server > or RT throttling. Can you please try disabling both of them: > > echo 0 | tee /sys/kernel/debug/sched/fair_server/cpu*/runtime > sysctl -w kernel.sched_rt_runtime_us=-1 > > and see if the problem persists?
My bad, that was the fair server's doing, ignore what I said. > > > It seems perfectly reasonable from the monitor description but it's > > actually a behaviour meant to improve real time response. > > Is the user seeing this type of violation supposed to make sure all > > locks held by RT tasks are never shared by fair tasks? If that's > > the case I'd mention it in the description. > > Boosted fair tasks are treated as RT tasks ;) > > > Also very rarely I see failures while cleaning up the monitor, not > > sure exactly what caused it but I could reproduce it with something > > like: > > > > for i in $(seq 100); do timeout -s INT 2 rv mon rts -r printk; > > done > > > > Running the monitor without stopping for the same amount of time > > doesn't seem to show violations (until I terminate it). > > This one is strange, I cannot reproduce this issue. Did you run only > that command, or did you have other things running as well? > > And does the problem still appears after disabling the fair deadline > server and RT throttling? Also here, I don't seem to reproduce it with both disabled.. Sorry for that, looks good for me then. Reviewed-by: Gabriele Monaco <gmon...@redhat.com> Thanks, Gabriele
