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From:   Vincent Guittot <vincent.guittot@linaro.org>
Date:   Thu, 7 Jul 2022 08:42:59 +0200
Message-ID: <CAKfTPtCTrHpNTU66ozFqL0uPy6Rwz-PppbummH4Rd_E7ZUzbnw@mail.gmail.com>
Subject: Re: [PATCH] sched/fair: fix case with reduced capacity CPU
To:     David Chen <david.chen@nutanix.com>
Cc:     Zhang Qiao <zhangqiao22@huawei.com>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "juri.lelli@redhat.com" <juri.lelli@redhat.com>,
        "dietmar.eggemann@arm.com" <dietmar.eggemann@arm.com>,
        "rostedt@goodmis.org" <rostedt@goodmis.org>,
        "bsegall@google.com" <bsegall@google.com>,
        "mgorman@suse.de" <mgorman@suse.de>,
        "bristot@redhat.com" <bristot@redhat.com>,
        "vschneid@redhat.com" <vschneid@redhat.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
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On Wed, 6 Jul 2022 at 01:50, David Chen <david.chen@nutanix.com> wrote:
>
>
>
> > -----Original Message-----
> > From: Zhang Qiao <zhangqiao22@huawei.com>
> > Sent: Tuesday, July 5, 2022 1:23 AM
> > To: Vincent Guittot <vincent.guittot@linaro.org>
> > Cc: mingo@redhat.com; peterz@infradead.org; juri.lelli@redhat.com; diet=
mar.eggemann@arm.com; rostedt@goodmis.org;
> > bsegall@google.com; mgorman@suse.de; bristot@redhat.com; vschneid@redha=
t.com; linux-kernel@vger.kernel.org; David Chen
> > <david.chen@nutanix.com>
> > Subject: Re: [PATCH] sched/fair: fix case with reduced capacity CPU
> >
> >
> >
> > =E5=9C=A8 2022/7/2 12:52, Vincent Guittot =E5=86=99=E9=81=93:
> > > The capacity of the CPU available for CFS tasks can be reduced becaus=
e of
> > > other activities running on the latter. In such case, it's worth tryi=
ng to
> > > move CFS tasks on a CPU with more available capacity.
> > >
> > > The rework of the load balance has filterd the case when the CPU is
> > > classified to be fully busy but its capacity is reduced.
> > >
> > > Check if CPU's capacity is reduced while gathering load balance stati=
stics
> > > and classify it group_misfit_task instead of group_fully_busy so we c=
an
> > > try to move the load on another CPU.
> > >
> > > Reported-by: David Chen <david.chen@nutanix.com>
> > > Reported-by: Zhang Qiao <zhangqiao22@huawei.com>
> > > Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
> > > ---
> > >
> > > David, Zhang,
> > >
> > > I haven't put your tested-by because I have reworked and cleaned the =
patch to
> > > cover more cases.
> > >
> > > Could you run some tests with this version ?
> >
> > I tested with this version, it is ok.
> >
> > Tested-by: Zhang Qiao <zhangqiao22@huawei.com>
> >
> > Thanks
>
> This version works fine with me.
> Tested-by: David Chen <david.chen@nutanix.com>

Thanks

>
> Thanks
>

> > >