Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:1 as permitted sender) client-ip=2620:137:e000::3:1;
Date:   Fri, 20 Oct 2023 17:32:07 -0300
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 v4] perf bench sched pipe: Add -G/--cgroups option
Message-ID: <ZTLjx3A8LBQMYWHJ@kernel.org>
References: <20231017202342.1353124-1-namhyung@kernel.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20231017202342.1353124-1-namhyung@kernel.org>
Precedence: bulk

Em Tue, Oct 17, 2023 at 01:23:42PM -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.
<SNIP>
>   > 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

Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>

[root@five ~]# perf stat -e context-switches,cgroup-switches taskset -c 0 perf bench sched pipe -l 10000
# Running 'sched/pipe' benchmark:
# Executed 10000 pipe operations between two processes

     Total time: 0.063 [sec]

       6.367500 usecs/op
         157047 ops/sec

 Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 10000':

            20,004      context-switches
                 4      cgroup-switches

       0.084191842 seconds time elapsed

       0.008332000 seconds user
       0.067193000 seconds sys


[root@five ~]# perf stat -e context-switches,cgroup-switches taskset -c 0 perf bench sched pipe -l 10000 -G AAA,BBB
# Running 'sched/pipe' benchmark:
no access to cgroup /sys/fs/cgroup/BBB
Failed to open cgroup file in BBB
 Hint: create the cgroup first, like 'mkdir /sys/fs/cgroup/BBB'
no access to cgroup /sys/fs/cgroup/AAA
Failed to open cgroup file in AAA
 Hint: create the cgroup first, like 'mkdir /sys/fs/cgroup/AAA'

 Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 10000 -G AAA,BBB':

                 2      context-switches
                 1      cgroup-switches

       0.010356533 seconds time elapsed

       0.003209000 seconds user
       0.007122000 seconds sys


[root@five ~]# vim /tmp/bla
[root@five ~]#
[root@five ~]# mkdir /sys/fs/cgroup/BBB /sys/fs/cgroup/AAA
[root@five ~]# perf stat -e context-switches,cgroup-switches taskset -c 0 perf bench sched pipe -l 10000 -G AAA,BBB
# Running 'sched/pipe' benchmark:
# Executed 10000 pipe operations between two processes

     Total time: 0.079 [sec]

       7.987800 usecs/op
         125190 ops/sec

 Performance counter stats for 'taskset -c 0 perf bench sched pipe -l 10000 -G AAA,BBB':

            20,008      context-switches
            20,007      cgroup-switches

       0.089361029 seconds time elapsed

       0.009004000 seconds user
       0.065376000 seconds sys


[root@five ~]#