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[23.128.96.18]) by mx.google.com with ESMTP id a7si7145jat.120.2021.05.19.11.18.03; Wed, 19 May 2021 11:18:16 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=LwA0jhoc; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243830AbhEROym (ORCPT + 99 others); Tue, 18 May 2021 10:54:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:60886 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235888AbhEROyk (ORCPT ); Tue, 18 May 2021 10:54:40 -0400 Received: from mail-lj1-x236.google.com (mail-lj1-x236.google.com [IPv6:2a00:1450:4864:20::236]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C9AB5C061756 for ; Tue, 18 May 2021 07:53:21 -0700 (PDT) Received: by mail-lj1-x236.google.com with SMTP id p20so11925576ljj.8 for ; Tue, 18 May 2021 07:53:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=fjg3qZs5k6I/97/2j2zryLOYba1okHDNwQ2ngYD7gmk=; b=LwA0jhocjIDkDCwgZ0OZcCFjqpnw2V0xSzfMAlQdZAOQGIrV9GBnO70USBBEv9zO2k p1YwV1+5v/q5SkZCI7X0f7Qct9ZwFynXefhV7wgMQuGN8uPVmMcaKpj1ogQXCnEZSX2p umL8I2s1e72TiY9IHZhKiTpEqqmQ8sxRi9sp2qe05EiVa83+bYm7iYP26wYlPG3LT30H gPGcyAjAlD1WbZHZCMH7be0HJ1XvnFbh2+Y2INQgyy4h1Ur4FZWqqNhJ5aMBH6Sf4aaw OFyLgxcZNOia6IxyxagPfQ5pETOqRZXv0u16+7bssu4KpYF0GvOX5GQRYAqwICq3TZx7 IYfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=fjg3qZs5k6I/97/2j2zryLOYba1okHDNwQ2ngYD7gmk=; b=BZpLDYcWXgp2J1nMZ+U3Z7Xh2SgpwawCXqSrn2g6aJbXjmzpkfJJ/k8F1qEVRs38PC 8W5v3ft/BkUdEoVQ6/+1lMk5Mx+NN+Zh0BcugdgeLC36KGgAboITI1mrEa7mzCLPkkOK xlRzzkCXXXyytzy29jbkTz677V3Ip+AHYDClmwRu4e1uDfF/pKphONSL/Fn69o43XTpu Y1hcbT7zJ9yoGK72vP8ayMZ84XBLksc0fqVPUT9CCs05gnnSg9Ta5DbzL58jIpRBwUJP IXMNaLQAttATs7M8xb0BtlKAP4MOADmGUcErmFnipSQOgQbURlQWCpFjZ+Q8wRdvGeOS Q+AQ== X-Gm-Message-State: AOAM532qGeYyOd5u5/fQfus4VjUPUFl+L7xMv9WJr4EvxWq1iGNDWXal c5YGbslacy3Cs82YR2HPowZ7nG8LfDl4Gqp8Z2vJxg== X-Received: by 2002:a2e:8557:: with SMTP id u23mr4357444ljj.221.1621349600234; Tue, 18 May 2021 07:53:20 -0700 (PDT) MIME-Version: 1.0 References: <1621239831-5870-1-git-send-email-beata.michalska@arm.com> <1621239831-5870-2-git-send-email-beata.michalska@arm.com> <20210518142746.GA3993@e120325.cambridge.arm.com> In-Reply-To: <20210518142746.GA3993@e120325.cambridge.arm.com> From: Vincent Guittot Date: Tue, 18 May 2021 16:53:09 +0200 Message-ID: Subject: Re: [PATCH v4 1/3] sched/core: Introduce SD_ASYM_CPUCAPACITY_FULL sched_domain flag To: Beata Michalska Cc: linux-kernel , Peter Zijlstra , Ingo Molnar , Juri Lelli , Valentin Schneider , Dietmar Eggemann , "corbet@lwn.net" , Randy Dunlap , Linux Doc Mailing List Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 18 May 2021 at 16:27, Beata Michalska wrote: > > On Tue, May 18, 2021 at 03:39:27PM +0200, Vincent Guittot wrote: > > On Mon, 17 May 2021 at 10:24, Beata Michalska wrote: > > > > > > Introducing new, complementary to SD_ASYM_CPUCAPACITY, sched_domain > > > topology flag, to distinguish between shed_domains where any CPU > > > capacity asymmetry is detected (SD_ASYM_CPUCAPACITY) and ones where > > > a full range of CPU capacities is visible to all domain members > > > (SD_ASYM_CPUCAPACITY_FULL). > > > > I'm not sure about what you want to detect: > > > > Is it a sched_domain level with a full range of cpu capacity, i.e. > > with at least 1 min capacity and 1 max capacity ? > > or do you want to get at least 1 cpu of each capacity ? > That would be at least one CPU of each available capacity within given domain, > so full -set- of available capacities within a domain. Would be good to add the precision. Although I'm not sure if that's the best policy compared to only getting the range which would be far simpler to implement. Do you have some topology example ? > > --- > BR > B. > > > > > > > > > > With the distinction between full and partial CPU capacity asymmetry, > > > brought in by the newly introduced flag, the scope of the original > > > SD_ASYM_CPUCAPACITY flag gets shifted, still maintaining the existing > > > behaviour when one is detected on a given sched domain, allowing > > > misfit migrations within sched domains that do not observe full range > > > of CPU capacities but still do have members with different capacity > > > values. It loses though it's meaning when it comes to the lowest CPU > > > asymmetry sched_domain level per-cpu pointer, which is to be now > > > denoted by SD_ASYM_CPUCAPACITY_FULL flag. > > > > > > Signed-off-by: Beata Michalska > > > Reviewed-by: Valentin Schneider > > > --- > > > include/linux/sched/sd_flags.h | 10 ++++++++++ > > > 1 file changed, 10 insertions(+) > > > > > > diff --git a/include/linux/sched/sd_flags.h b/include/linux/sched/sd_flags.h > > > index 34b21e9..57bde66 100644 > > > --- a/include/linux/sched/sd_flags.h > > > +++ b/include/linux/sched/sd_flags.h > > > @@ -91,6 +91,16 @@ SD_FLAG(SD_WAKE_AFFINE, SDF_SHARED_CHILD) > > > SD_FLAG(SD_ASYM_CPUCAPACITY, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) > > > > > > /* > > > + * Domain members have different CPU capacities spanning all unique CPU > > > + * capacity values. > > > + * > > > + * SHARED_PARENT: Set from the topmost domain down to the first domain where > > > + * all available CPU capacities are visible > > > + * NEEDS_GROUPS: Per-CPU capacity is asymmetric between groups. > > > + */ > > > +SD_FLAG(SD_ASYM_CPUCAPACITY_FULL, SDF_SHARED_PARENT | SDF_NEEDS_GROUPS) > > > + > > > +/* > > > * Domain members share CPU capacity (i.e. SMT) > > > * > > > * SHARED_CHILD: Set from the base domain up until spanned CPUs no longer share > > > -- > > > 2.7.4 > > >