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 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 DE48CC4708F for ; Tue, 1 Jun 2021 08:09:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BD9E96128A for ; Tue, 1 Jun 2021 08:09:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233272AbhFAIKy convert rfc822-to-8bit (ORCPT ); Tue, 1 Jun 2021 04:10:54 -0400 Received: from szxga08-in.huawei.com ([45.249.212.255]:3314 "EHLO szxga08-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233056AbhFAIKx (ORCPT ); Tue, 1 Jun 2021 04:10:53 -0400 Received: from dggemv711-chm.china.huawei.com (unknown [172.30.72.57]) by szxga08-in.huawei.com (SkyGuard) with ESMTP id 4FvPnm4SyMz19S3m; Tue, 1 Jun 2021 16:04:28 +0800 (CST) Received: from dggpeml100021.china.huawei.com (7.185.36.148) by dggemv711-chm.china.huawei.com (10.1.198.66) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Tue, 1 Jun 2021 16:09:09 +0800 Received: from dggemi761-chm.china.huawei.com (10.1.198.147) by dggpeml100021.china.huawei.com (7.185.36.148) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2176.2; Tue, 1 Jun 2021 16:09:09 +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, 1 Jun 2021 16:09:09 +0800 From: "Song Bao Hua (Barry Song)" To: Mel Gorman CC: Peter Zijlstra , "vincent.guittot@linaro.org" , "mingo@redhat.com" , "dietmar.eggemann@arm.com" , "rostedt@goodmis.org" , "bsegall@google.com" , "valentin.schneider@arm.com" , "juri.lelli@redhat.com" , "bristot@redhat.com" , "linux-kernel@vger.kernel.org" , "guodong.xu@linaro.org" , yangyicong , tangchengchang , Linuxarm Subject: RE: [PATCH] sched: fair: don't depend on wake_wide if waker and wakee are already in same LLC Thread-Topic: [PATCH] sched: fair: don't depend on wake_wide if waker and wakee are already in same LLC Thread-Index: AQHXUhAXdUizMfoReUmU6BSpTsz4hqr1J2iAgAEbn9CAAHZUgIAHdICQgAAf8wCAAIRPEA== Date: Tue, 1 Jun 2021 08:09:09 +0000 Message-ID: <75ec9e490d1d4854ae2be4ad5b3b24b9@hisilicon.com> References: <20210526091057.1800-1-song.bao.hua@hisilicon.com> <7dd00a98d6454d5e92a7d9b936d1aa1c@hisilicon.com> <20210527121409.GK3672@suse.de> <07e4ba63a19c451ab47e6a636c400f4a@hisilicon.com> <20210601075918.GP3672@suse.de> In-Reply-To: <20210601075918.GP3672@suse.de> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.126.201.217] 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: Mel Gorman [mailto:mgorman@suse.de] > Sent: Tuesday, June 1, 2021 7:59 PM > To: Song Bao Hua (Barry Song) > Cc: Peter Zijlstra ; vincent.guittot@linaro.org; > mingo@redhat.com; dietmar.eggemann@arm.com; rostedt@goodmis.org; > bsegall@google.com; valentin.schneider@arm.com; juri.lelli@redhat.com; > bristot@redhat.com; linux-kernel@vger.kernel.org; guodong.xu@linaro.org; > yangyicong ; tangchengchang > ; Linuxarm > Subject: Re: [PATCH] sched: fair: don't depend on wake_wide if waker and wakee > are already in same LLC > > On Mon, May 31, 2021 at 10:21:55PM +0000, Song Bao Hua (Barry Song) wrote: > > The benchmark of tbenchs is still positive: > > > > tbench4 > > > > 5.13-rc4 5.13-rc4 > > disable-llc-wakewide/ > > > > Hmean 1 514.87 ( 0.00%) 505.17 * -1.88%* > > Hmean 2 914.45 ( 0.00%) 918.45 * 0.44%* > > Hmean 4 1483.81 ( 0.00%) 1485.38 * 0.11%* > > Hmean 8 2211.62 ( 0.00%) 2236.02 * 1.10%* > > Hmean 16 2129.80 ( 0.00%) 2450.81 * 15.07%* > > Hmean 32 5098.35 ( 0.00%) 5085.20 * -0.26%* > > Hmean 64 4797.62 ( 0.00%) 4801.34 * 0.08%* > > Hmean 80 4802.89 ( 0.00%) 4780.40 * -0.47%* > > > > I guess something which work across several LLC domains > > cause performance regression. > > > > I wonder how your test will be like if you pin the testing > > to CPUs within one LLC? > > > > While I could do this, what would be the benefit? Running within one LLC > would be running the test in one small fraction of the entire machine as > the machine has multiple LLCs per NUMA node. A patch dealing with how the > scheduler works with respect to LLC should take different configurations > into consideration as best as possible. I do agree with this. And I do admit this patch is lacking of consideration and testing of supporting various configurations. But more input of numbers will be helpful on figuring out a better solution which can either extend to wider configurations or shrink to some specific machines like those whose whole numa share LLC or desktops whose all cpus share LLC in v2. eg: My pc with the newest i9 intel has all 10 cpus(20 threads) sharing LLC. > > -- > Mel Gorman > SUSE Labs Thanks Barry