On 2/23/23 09:12, Prasad Pandit wrote: > Hello Daniel, > > On Thu, 23 Feb 2023 at 00:41, Prasad Pandit <ppandit@xxxxxxxxxx> wrote: >> # trace-cmd record -p nop -e all -M 0x7FE -m 32000 --poll ~test/rt-tests/oslat --cpu-list 1-10 --duration 1h -w memmove -m 4K -T20 >> .... >> Maximum: 14 11 13 12 12 13 12 11 12 10 (us) >> Max-Min: 13 10 12 11 11 12 11 10 11 9 (us) >> Duration: 3599.986 3599.986 3599.987 3599.987 3599.986 3599.987 3599.986 3599.987 3599.986 3599.986 (sec) >> >> * Running oslat(1) with SCHED_OTHER priority via 'trace-cmd --poll' option, did not show the spike. Nonetheless, trace-cmd(1) logs show <idle>, ktimers/ and kworker/ threads running on isolated CPUs. >> * Now running rtla-osnoise(1) test with SCHED_OTHER: >> # rtla osnoise top -c 1-10 -d 6h -s 20 -T 20 -Po:0 -q -t > > Please see: > -> https://0bin.net/paste/ShXHmdvu#D0XY-WxTKCzWTxgQ+lTFbx1nB2TP2w+T0Mp8PBXt9gu > > * rtla-osnoise(1) running for 6 hours with SCHED_OTHER and SCHED_FIFO, > both did not report any spike above 20us. Good! > It's reporting occurrence of IRQs only, all other noise columns are > zero(0). That's a little surprising!? Regarding the IRQs only: That is a good sign! your isolation is good! Regarding the numbers: -T 20 is saying to the tracer to account as noise only noise >= 20 us. As you did not hit a single case as your -s20 did not stop the trace, that is expected. But I think that what you want is -T 1. That is, consider a noise anything that is > than 1 us. This will show you the noise added by those IRQs. Anyways, the isolation is good enough to have good numbers with SCHED_OTHER... without risks of starvation. > Thank you. > --- > - Prasad >
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