From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
linux-perf-users@vger.kernel.org
Subject: Re: [PATCH] perf bench sched pipe: Add -G/--cgroups option
Date: Fri, 13 Oct 2023 20:03:34 -0300 [thread overview]
Message-ID: <ZSnMxtnt7o5mLj+w@kernel.org> (raw)
In-Reply-To: <CAM9d7cip5qmPRhWF37JH_21Q8SjKQCTBVyF_PLE-ytTFOwpasg@mail.gmail.com>
Em Fri, Oct 13, 2023 at 03:57:27PM -0700, Namhyung Kim escreveu:
> Hi Arnaldo,
>
> On Fri, Oct 13, 2023 at 3:41 PM Arnaldo Carvalho de Melo
> <acme@kernel.org> wrote:
> >
> > Em Wed, Oct 04, 2023 at 01:47:41PM -0700, Namhyung Kim escreveu:
> > > The -G/--cgroups option is to put sender and receiver in different
> > > cgroups in order to measure cgroup context switch overheads.
> > >
> > > Users need to make sure the cgroups exist and accessible.
> > >
> > > # perf stat -e context-switches,cgroup-switches \
> > > > taskset -c 0 perf bench sched pipe -l 10000 > /dev/null
> > >
> > > Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 10000':
> > >
> > > 20,001 context-switches
> > > 2 cgroup-switches
> > >
> > > 0.053449651 seconds time elapsed
> > >
> > > 0.011286000 seconds user
> > > 0.041869000 seconds sys
> > >
> > > # perf stat -e context-switches,cgroup-switches \
> > > > taskset -c 0 perf bench sched pipe -l 10000 -G AAA,BBB > /dev/null
> > >
> > > Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 10000 -G AAA,BBB':
> > >
> > > 20,001 context-switches
> > > 20,001 cgroup-switches
> > >
> > > 0.052768627 seconds time elapsed
> >
> > So I tried with:
> >
> > [root@quaco ~]# perf bench sched pipe -G system.slice,user.slice
> > # Running 'sched/pipe' benchmark:
> > cannot enter to cgroup: system.slice
> > cannot enter to cgroup: user.slice
> > # Executed 1000000 pipe operations between two processes
> >
> > Total time: 6.301 [sec]
> >
> > 6.301478 usecs/op
> > 158692 ops/sec
> > [root@quaco ~]#
> >
> > Should't it bail out when not managing to enter the cgroups?
>
> Hmm.. right. Will fix.
>
> >
> > Also:
> >
> > [root@quaco ~]# mkdir /sys/fs/cgroup/AAA
> > [root@quaco ~]# mkdir /sys/fs/cgroup/BBB
> > [root@quaco ~]#
> > [root@quaco ~]# perf bench sched pipe -G AAA,BBB
> > # Running 'sched/pipe' benchmark:
> > cannot enter to cgroup: AAA
> > cannot enter to cgroup: BBB
> > # Executed 1000000 pipe operations between two processes
> >
> > Total time: 6.397 [sec]
> >
> > 6.397830 usecs/op
> > 156302 ops/sec
> > [root@quaco ~]#
> >
> > -rw-r--r--. 1 root root 0 Oct 13 19:22 /sys/fs/cgroup/AAA/cgroup.procs
> > [root@quaco ~]# ls -la /sys/fs/cgroup/AAA/cgroup.threads
> > -rw-r--r--. 1 root root 0 Oct 13 19:22 /sys/fs/cgroup/AAA/cgroup.threads
> > [root@quaco ~]# ls -la /sys/fs/cgroup/BBB/cgroup.threads
> > -rw-r--r--. 1 root root 0 Oct 13 19:22 /sys/fs/cgroup/BBB/cgroup.threads
> > [root@quaco ~]# ls -la /sys/fs/cgroup/BBB/cgroup.procs
> > -rw-r--r--. 1 root root 0 Oct 13 19:22 /sys/fs/cgroup/BBB/cgroup.procs
> > [root@quaco ~]#
> >
> > [root@quaco ~]# perf bench sched pipe -G AAA,BBB
> > # Running 'sched/pipe' benchmark:
> > cannot enter to cgroup: AAA (written=-1, len=6, errno=Operation not supported)
> > cannot enter to cgroup: BBB (written=-1, len=6, errno=Operation not supported)
> > # Executed 1000000 pipe operations between two processes
> >
> > Total time: 6.303 [sec]
> >
> > 6.303221 usecs/op
> > 158649 ops/sec
> > [root@quaco ~]#
> >
> > I'm certainly missing something here :-\
>
> Try to enable some cgroup controllers first. Like
>
> # echo +cpu > /sys/fs/cgroup/AAA/cgroup.subtree_control
> # echo +cpu > /sys/fs/cgroup/BBB/cgroup.subtree_control
[root@quaco cgroup]# echo +cpu > /sys/fs/cgroup/AAA/cgroup.subtree_control
[root@quaco cgroup]# echo +cpu > /sys/fs/cgroup/BBB/cgroup.subtree_control
[root@quaco cgroup]# perf bench sched pipe -G AAA,BBB
# Running 'sched/pipe' benchmark:
cannot enter to cgroup: AAA (written=-1, len=6, errno=Operation not supported)
cannot enter to cgroup: BBB (written=-1, len=6, errno=Operation not supported)
# Executed 1000000 pipe operations between two processes
Total time: 6.267 [sec]
6.267680 usecs/op
159548 ops/sec
[root@quaco cgroup]# cat /sys/fs/cgroup/AAA/cgroup.subtree_control
cpu
[root@quaco cgroup]# cat /sys/fs/cgroup/BBB/cgroup.subtree_control
cpu
[root@quaco cgroup]# uname -a
Linux quaco 6.5.6-200.fc38.x86_64 #1 SMP PREEMPT_DYNAMIC Fri Oct 6 19:02:35 UTC 2023 x86_64 GNU/Linux
[root@quaco cgroup]#
next prev parent reply other threads:[~2023-10-13 23:03 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-04 20:47 [PATCH] perf bench sched pipe: Add -G/--cgroups option Namhyung Kim
2023-10-13 22:40 ` Arnaldo Carvalho de Melo
2023-10-13 22:57 ` Namhyung Kim
2023-10-13 23:03 ` Arnaldo Carvalho de Melo [this message]
2023-10-13 23:10 ` Namhyung Kim
2023-10-13 23:20 ` Namhyung Kim
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