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From:   Shakeel Butt <shakeelb@google.com>
Date:   Wed, 11 Oct 2023 05:45:58 -0700
Message-ID: <CALvZod7NN-9Vvy=KRtFZfV7SUzD+Bn8Z8QSEdAyo48pkOAHtTg@mail.gmail.com>
Subject: Re: [PATCH v2 3/5] mm: memcg: make stats flushing threshold per-memcg
To:     Yosry Ahmed <yosryahmed@google.com>
Cc:     Andrew Morton <akpm@linux-foundation.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Muchun Song <muchun.song@linux.dev>,
        Ivan Babrou <ivan@cloudflare.com>, Tejun Heo <tj@kernel.org>,
        =?UTF-8?Q?Michal_Koutn=C3=BD?= <mkoutny@suse.com>,
        Waiman Long <longman@redhat.com>, kernel-team@cloudflare.com,
        Wei Xu <weixugc@google.com>, Greg Thelen <gthelen@google.com>,
        linux-mm@kvack.org, cgroups@vger.kernel.org,
        linux-kernel@vger.kernel.org
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On Tue, Oct 10, 2023 at 6:48=E2=80=AFPM Yosry Ahmed <yosryahmed@google.com>=
 wrote:
>
> On Tue, Oct 10, 2023 at 5:36=E2=80=AFPM Shakeel Butt <shakeelb@google.com=
> wrote:
> >
> > On Tue, Oct 10, 2023 at 03:21:47PM -0700, Yosry Ahmed wrote:
> > [...]
> > >
> > > I tried this on a machine with 72 cpus (also ixion), running both
> > > netserver and netperf in /sys/fs/cgroup/a/b/c/d as follows:
> > > # echo "+memory" > /sys/fs/cgroup/cgroup.subtree_control
> > > # mkdir /sys/fs/cgroup/a
> > > # echo "+memory" > /sys/fs/cgroup/a/cgroup.subtree_control
> > > # mkdir /sys/fs/cgroup/a/b
> > > # echo "+memory" > /sys/fs/cgroup/a/b/cgroup.subtree_control
> > > # mkdir /sys/fs/cgroup/a/b/c
> > > # echo "+memory" > /sys/fs/cgroup/a/b/c/cgroup.subtree_control
> > > # mkdir /sys/fs/cgroup/a/b/c/d
> > > # echo 0 > /sys/fs/cgroup/a/b/c/d/cgroup.procs
> > > # ./netserver -6
> > >
> > > # echo 0 > /sys/fs/cgroup/a/b/c/d/cgroup.procs
> > > # for i in $(seq 10); do ./netperf -6 -H ::1 -l 60 -t TCP_SENDFILE --
> > > -m 10K; done
> >
> > You are missing '&' at the end. Use something like below:
> >
> > #!/bin/bash
> > for i in {1..22}
> > do
> >    /data/tmp/netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K &
> > done
> > wait
> >
>
> Oh sorry I missed the fact that you are running instances in parallel, my=
 bad.
>
> So I ran 36 instances on a machine with 72 cpus. I did this 10 times
> and got an average from all instances for all runs to reduce noise:
>
> #!/bin/bash
>
> ITER=3D10
> NR_INSTANCES=3D36
>
> for i in $(seq $ITER); do
>   echo "iteration $i"
>   for j in $(seq $NR_INSTANCES); do
>     echo "iteration $i" >> "out$j"
>     ./netperf -6 -H ::1 -l 60 -t TCP_SENDFILE -- -m 10K >> "out$j" &
>   done
>   wait
> done
>
> cat out* | grep 540000 | awk '{sum +=3D $5} END {print sum/NR}'
>
> Base: 22169 mbps
> Patched: 21331.9 mbps
>
> The difference is ~3.7% in my runs. I am not sure what's different.
> Perhaps it's the number of runs?

My base kernel is next-20231009 and I am running experiments with
hyperthreading disabled.