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=-3.7 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 688DDC64E8A for ; Thu, 3 Dec 2020 09:58:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0CE6422253 for ; Thu, 3 Dec 2020 09:58:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388528AbgLCJ54 convert rfc822-to-8bit (ORCPT ); Thu, 3 Dec 2020 04:57:56 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:2198 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730121AbgLCJ5z (ORCPT ); Thu, 3 Dec 2020 04:57:55 -0500 Received: from fraeml715-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4Cmrmg6RY4z67Hq5; Thu, 3 Dec 2020 17:55:15 +0800 (CST) Received: from lhreml714-chm.china.huawei.com (10.201.108.65) by fraeml715-chm.china.huawei.com (10.206.15.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2106.2; Thu, 3 Dec 2020 10:57:12 +0100 Received: from dggemi761-chm.china.huawei.com (10.1.198.147) by lhreml714-chm.china.huawei.com (10.201.108.65) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.1913.5; Thu, 3 Dec 2020 09:57:11 +0000 Received: from dggemi761-chm.china.huawei.com ([10.9.49.202]) by dggemi761-chm.china.huawei.com ([10.9.49.202]) with mapi id 15.01.1913.007; Thu, 3 Dec 2020 17:57:09 +0800 From: "Song Bao Hua (Barry Song)" To: Peter Zijlstra , Valentin Schneider CC: "catalin.marinas@arm.com" , "will@kernel.org" , "rjw@rjwysocki.net" , "lenb@kernel.org" , "gregkh@linuxfoundation.org" , Jonathan Cameron , "mingo@redhat.com" , "juri.lelli@redhat.com" , "vincent.guittot@linaro.org" , "dietmar.eggemann@arm.com" , "rostedt@goodmis.org" , "bsegall@google.com" , "mgorman@suse.de" , "mark.rutland@arm.com" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux-acpi@vger.kernel.org" , Linuxarm , "xuwei (O)" , "Zengtao (B)" Subject: RE: [RFC PATCH v2 2/2] scheduler: add scheduler level for clusters Thread-Topic: [RFC PATCH v2 2/2] scheduler: add scheduler level for clusters Thread-Index: AQHWx46tyJL5OgLpakCat9sEfhhBKKnh4fQAgAK2JoCAAItncA== Date: Thu, 3 Dec 2020 09:57:09 +0000 Message-ID: References: <20201201025944.18260-1-song.bao.hua@hisilicon.com> <20201201025944.18260-3-song.bao.hua@hisilicon.com> <20201203092831.GH2414@hirez.programming.kicks-ass.net> In-Reply-To: <20201203092831.GH2414@hirez.programming.kicks-ass.net> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.126.200.109] 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: Peter Zijlstra [mailto:peterz@infradead.org] > Sent: Thursday, December 3, 2020 10:29 PM > To: Valentin Schneider > Cc: Song Bao Hua (Barry Song) ; > catalin.marinas@arm.com; will@kernel.org; rjw@rjwysocki.net; lenb@kernel.org; > gregkh@linuxfoundation.org; Jonathan Cameron ; > mingo@redhat.com; juri.lelli@redhat.com; vincent.guittot@linaro.org; > dietmar.eggemann@arm.com; rostedt@goodmis.org; bsegall@google.com; > mgorman@suse.de; mark.rutland@arm.com; linux-arm-kernel@lists.infradead.org; > linux-kernel@vger.kernel.org; linux-acpi@vger.kernel.org; Linuxarm > ; xuwei (O) ; Zengtao (B) > > Subject: Re: [RFC PATCH v2 2/2] scheduler: add scheduler level for clusters > > On Tue, Dec 01, 2020 at 04:04:04PM +0000, Valentin Schneider wrote: > > > > Gating this behind this new config only leveraged by arm64 doesn't make it > > very generic. Note that powerpc also has this newish "CACHE" level which > > seems to overlap in function with your "CLUSTER" one (both are arch > > specific, though). > > > > I think what you are after here is an SD_SHARE_PKG_RESOURCES domain walk, > > i.e. scan CPUs by increasing cache "distance". We already have it in some > > form, as we scan SMT & LLC domains; AFAICT LLC always maps to MC, except > > for said powerpc's CACHE thingie. > > There's some intel chips with a smaller L2, but I don't think we ever > bothered. > > There's also the extended topology stuff from Intel: SMT, Core, Module, > Tile, Die, of which we've only partially used Die I think. > > Whatever we do, it might make sense to not all use different names. Yep. Valentin was actually recommending the same SD_SHARE_PKG_RESOURCES sd flags by ignoring the actual names of the hardware. But the question is where we should start, in case we have 3 domains under llc, maybe it is not good to scan from the first level domain as it is gathering too much. > > Also, I think Mel said he was cooking something for > select_idle_balance(). > > Also, I've previously posted patches that fold all the iterations into > one, so it might make sense to revisit some of that if Mel also already > didn.t Would you point out the link of your previous patches? Thanks Barry