On Wed, 31 May 2023 at 12:50, Lukáš Doktor <ldok...@redhat.com> wrote: > > Dne 26. 05. 23 v 12:56 Stefan Hajnoczi napsal(a): > > On Fri, 26 May 2023 at 04:07, Lukáš Doktor <ldok...@redhat.com> wrote: > >> > >> Dne 25. 05. 23 v 17:21 Stefan Hajnoczi napsal(a): > >>> On Thu, 25 May 2023 at 06:18, Lukáš Doktor <ldok...@redhat.com> wrote: > >>>> the perf-ci detected and bisected the 6d740fb - aio-posix: do not nest > >>>> poll handlers - as a performance improvement when using multiple > >>>> concurrent jobs and 4k (22%) as well as 1024k (63%) blocks on aarch64 > >>>> (on a slow rotational disk). > >>>> > >>>> > >>>> https://ldoktor.github.io/tmp/RedHat-virtlab-arm09/v8.0.0/150-improvement.html > >>>> > >>>> Based on the commit message I guess it's expected so take this just as a > >>>> record of an improvement. > >>> > >>> The commit was not intended to change performance and I'm not sure why > >>> it happens! > >>> > >> > >> It had and today the x86_64 pipeline finished which shows similar > >> improvement just not in read but rather in write instead and only for 4k > >> blocks (~40%). For 1024k blocks I can see it scoring a bit better (~1.5%). > >> Reads are too jittery to really tell anything on that machine. Anyway I > >> have not done any thorough testing, just a bisection with the most > >> significant setting. > >> > >> From around the same time I can see a NVMe regression in 4k writes, but > >> first bisection job showed nothing. I'll increase the range and try again > >> as each job since that day shows similar drop. > > > > Hello Stefan, folks, > > the regression proved to be there and stably reproducible. With NVMe 4k > writes with jobs=10 and iodepth=4 I can see a 50% regression on my machine: > > https://ldoktor.github.io/tmp/RedHat-virtlab722/v8.0.0/150-regression.html > > The rest of the cases doesn't show any change at all. I can provide more data > if someone is interested.
Which commit caused the regression? Stefan
