From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B76BBC433B4 for ; Tue, 27 Apr 2021 06:05:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 880EE61152 for ; Tue, 27 Apr 2021 06:05:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230169AbhD0GF7 convert rfc822-to-8bit (ORCPT ); Tue, 27 Apr 2021 02:05:59 -0400 Received: from szxga02-in.huawei.com ([45.249.212.188]:3957 "EHLO szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229578AbhD0GF5 (ORCPT ); Tue, 27 Apr 2021 02:05:57 -0400 Received: from dggeml763-chm.china.huawei.com (unknown [172.30.72.55]) by szxga02-in.huawei.com (SkyGuard) with ESMTP id 4FTrlQ4Zhwz5vms; Tue, 27 Apr 2021 14:02:42 +0800 (CST) Received: from dggpemm000002.china.huawei.com (7.185.36.174) by dggeml763-chm.china.huawei.com (10.1.199.173) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Tue, 27 Apr 2021 14:05:10 +0800 Received: from dggemi761-chm.china.huawei.com (10.1.198.147) by dggpemm000002.china.huawei.com (7.185.36.174) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Tue, 27 Apr 2021 14:05:09 +0800 Received: from dggemi761-chm.china.huawei.com ([10.9.49.202]) by dggemi761-chm.china.huawei.com ([10.9.49.202]) with mapi id 15.01.2176.012; Tue, 27 Apr 2021 14:05:09 +0800 From: "Song Bao Hua (Barry Song)" To: Mike Galbraith , "vincent.guittot@linaro.org" , "mingo@redhat.com" , "peterz@infradead.org" , "dietmar.eggemann@arm.com" , "rostedt@goodmis.org" , "bsegall@google.com" , "mgorman@suse.de" CC: "valentin.schneider@arm.com" , "juri.lelli@redhat.com" , "bristot@redhat.com" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "xuwei (O)" , "Zengtao (B)" , "guodong.xu@linaro.org" , yangyicong , "Liguozhu (Kenneth)" , "linuxarm@openeuler.org" , wanghuiqiang , "xieyongjia (A)" Subject: RE: [PATCH] sched/fair: don't use waker's cpu if the waker of sync wake-up is interrupt Thread-Topic: [PATCH] sched/fair: don't use waker's cpu if the waker of sync wake-up is interrupt Thread-Index: AQHXOw9dc8i42PiGaEKAYTXwXtRa3KrHPV0AgACFWFD//5SmAIAAhgYg Date: Tue, 27 Apr 2021 06:05:09 +0000 Message-ID: <6c91195a6de9423abc78e8f85efc2780@hisilicon.com> References: <20210427023758.4048-1-song.bao.hua@hisilicon.com> <9a6cadd9b65068b52c95adc44119bd09c6a4f9d7.camel@gmx.de> <3fe7113cc87ac89077b55ca55bda2b99729f13c8.camel@gmx.de> In-Reply-To: <3fe7113cc87ac89077b55ca55bda2b99729f13c8.camel@gmx.de> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.126.201.183] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > -----Original Message----- > From: Mike Galbraith [mailto:efault@gmx.de] > Sent: Tuesday, April 27, 2021 5:55 PM > To: Song Bao Hua (Barry Song) ; > vincent.guittot@linaro.org; mingo@redhat.com; peterz@infradead.org; > dietmar.eggemann@arm.com; rostedt@goodmis.org; bsegall@google.com; > mgorman@suse.de > Cc: valentin.schneider@arm.com; juri.lelli@redhat.com; bristot@redhat.com; > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; xuwei (O) > ; Zengtao (B) ; > guodong.xu@linaro.org; yangyicong ; Liguozhu (Kenneth) > ; linuxarm@openeuler.org; wanghuiqiang > ; xieyongjia (A) > Subject: Re: [PATCH] sched/fair: don't use waker's cpu if the waker of sync > wake-up is interrupt > > 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 :) Would you like to share the link you did before to filter interrupt wakeups? The wake up path has hundreds of lines of code, so I don't expect that reading preempt_count will cause visible performance losses to bot. But who knows :-) > > -Mike Thanks Barry