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Message-ID: <3fe7113cc87ac89077b55ca55bda2b99729f13c8.camel@gmx.de>
Subject: Re: [PATCH] sched/fair: don't use waker's cpu if the waker of sync
 wake-up is interrupt
From:   Mike Galbraith <efault@gmx.de>
To:     "Song Bao Hua (Barry Song)" <song.bao.hua@hisilicon.com>,
        "vincent.guittot@linaro.org" <vincent.guittot@linaro.org>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "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>
Cc:     "valentin.schneider@arm.com" <valentin.schneider@arm.com>,
        "juri.lelli@redhat.com" <juri.lelli@redhat.com>,
        "bristot@redhat.com" <bristot@redhat.com>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "xuwei (O)" <xuwei5@huawei.com>,
        "Zengtao (B)" <prime.zeng@hisilicon.com>,
        "guodong.xu@linaro.org" <guodong.xu@linaro.org>,
        yangyicong <yangyicong@huawei.com>,
        "Liguozhu (Kenneth)" <liguozhu@hisilicon.com>,
        "linuxarm@openeuler.org" <linuxarm@openeuler.org>,
        wanghuiqiang <wanghuiqiang@huawei.com>,
        "xieyongjia (A)" <xieyongjia1@huawei.com>
Date:   Tue, 27 Apr 2021 07:54:32 +0200
In-Reply-To: <d057eb13ec4e4643b314dd1652ffa9d4@hisilicon.com>
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On Tue, 2021-04-27 at 04:44 +0000, Song Bao Hua (Barry Song) wrote:
>
>
> I agree sync hint might have been overused by other kernel subsystem.
> But this patch will at least fix a case: sync waker is interrupt,
> in this case, the existing task has nothing to do with waker and wakee,
> so this case should be excluded from wake_affine_idle().

I long ago tried filtering interrupt wakeups, and met some surprises.
Wakeup twiddling always managing to end up being a rob Peter to pay
Paul operation despite our best efforts, here's hoping that your pile
of stolen cycles is small enough to escape performance bot notice :)

	-Mike