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,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 2FD7FC433FE for ; Thu, 10 Dec 2020 08:02:20 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C24FA23D37 for ; Thu, 10 Dec 2020 08:02:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C24FA23D37 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:To:Subject:Message-ID:Date:From:In-Reply-To: References:MIME-Version:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=fYgVzqqrKNitNwb5ToLL3YBiktOGxcHn9aombswiKYg=; b=bgGGNvXLkQhMom3AUhEq8YdlM RyId8uzY/x+FBEsYreoNSLGIBm+2BRVBVIdqAQ36zB3Gmwlsza5ZVX6Uyh+uuAnOLB8kaqcQcGjsF 5sbum2l1WVaZ5Ww0a7Wetvux4CHWlvZjHI6Rn2BDYhgGrKGFMzP+vbXuMwGXgIL6KFp8TJskMVgDj ul4HYrWsqU3orvwlbvtFtvWxeXa/CAi+PQEwPZWMuluYZ5W/wMmVQrtxqYAhsc7vfmFmqEh+P61Vx HhnhZrCxlDdonETtItmCzBFYL3erN4kGFtvMZwszRXT4M5+CknmbdbNmG6dW0ujzrYgR6VioDyg3I RNmmWqnjA==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1knGsu-00031G-Tr; Thu, 10 Dec 2020 08:01:08 +0000 Received: from mail-lj1-x244.google.com ([2a00:1450:4864:20::244]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1knGsp-0002zd-Uu for linux-arm-kernel@lists.infradead.org; Thu, 10 Dec 2020 08:01:07 +0000 Received: by mail-lj1-x244.google.com with SMTP id x23so5651481lji.7 for ; Thu, 10 Dec 2020 00:01:01 -0800 (PST) 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=EaxSgwGc3sav/Jepv9lFlJ7IXr1WPiMxzvqTvfFy4fg=; b=Tj1jgPerQPS7CM9LA290bWZTIFQ4w+Enn6sPGDh3Apdb14yarz/+olHKH1AaBJn9zS uSI1BOfU+QfyK5gq95ET7abOMKpli0lAZ7lTmp2AWAOa6WDCSludrLgvaXMtWsTb9Qux oGdb6Mi2Zgd+wSDVo9eoEbZd2bI5e6D0CsBwjoQqaNDQfW4h8klcxMMtIoDAu1yCQA1x ihzBVY1ExV6iDF1oWNduiZphp9hPTfsQWFMbH+HZshAa6E7JSRK3tB4533IwicpYTCLE 90yGntViPXkVAkqjf+lcETwyWVLXaWl15A/L2ttv84iWxEBI6HIOsc3kJ1slqUGxgpKc EbHA== 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=EaxSgwGc3sav/Jepv9lFlJ7IXr1WPiMxzvqTvfFy4fg=; b=lwLA5Y6jafqgXD/nt/U6YlH3GisFndXz+lpePT9WI0tmKOJAPubtPJ0huM6vY2WwmB hhC78FVbo6bUx/OKoavY2awPTFIiZGvWy8LxvccK5gIsu3bNs0l88coLUC5Lx8JH3jAi yqi8SI6ThqjZHHQAx2DFL9kd5gRDvxEFE082spZY99+6ejQYveZQzsniwOOb+pPyV7Po wsI2+Pco7t3LqnDQ4Sw8wWEkkfg9CrHZlUMSKlABn73uuD+iz+9bAwDDGaUY+cwIt3Me tn0yVUWia2GaDPYklptPQ1aMBMtQNKEYNKHPyyBVqUcKMN9QRZNd7V4pKvB7SxiocWr1 TRxw== X-Gm-Message-State: AOAM533KPmpNq/Xnc8XDihR4l56UiBxhqQUs3TZSKeRQu6S5Dz/NzALV 7XZb+XCfVaH2XcX912mCQgNZD6b3/NqI9uSanlnVSA== X-Google-Smtp-Source: ABdhPJzOgUpJG4+fhPdf2F3nwt/AecWP8IsaQZ6IvObBuSiIq5Gd85PVHwbY2ski+RfTwgtHGhE0AeQ/aYZmlUZ7XsA= X-Received: by 2002:a2e:8396:: with SMTP id x22mr2499130ljg.221.1607587260753; Thu, 10 Dec 2020 00:01:00 -0800 (PST) MIME-Version: 1.0 References: <20201208153501.1467-1-mgorman@techsingularity.net> <20201209143748.GP3371@techsingularity.net> In-Reply-To: <20201209143748.GP3371@techsingularity.net> From: Vincent Guittot Date: Thu, 10 Dec 2020 09:00:49 +0100 Message-ID: Subject: Re: [PATCH 0/4] Reduce scanning of runqueues in select_idle_sibling To: Mel Gorman X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201210_030104_290276_7E66E3D0 X-CRM114-Status: GOOD ( 17.17 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Juri Lelli , Barry Song , Peter Ziljstra , Aubrey Li , LKML , Ingo Molnar , Valentin Schneider , Linux-ARM Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 9 Dec 2020 at 15:37, Mel Gorman wrote: > > On Tue, Dec 08, 2020 at 03:34:57PM +0000, Mel Gorman wrote: > > Changelog since v1 > > o Drop single-pass patch (vincent) > > o Scope variables used for SIS_AVG_CPU (dietmar) > > o Remove redundant assignment (dietmar > > > > This reduces the amount of runqueue scanning in select_idle_sibling in > > the worst case. > > > > Patch 1 removes SIS_AVG_CPU because it's unused. > > > > Patch 2 moves all SIS_PROP-related calculations under SIS_PROP > > > > Patch 3 improves the hit rate of p->recent_used_cpu to reduce the amount > > of scanning. It should be relatively uncontroversial > > > > Patch 4 returns an idle candidate if one is found while scanning for a > > free core. > > > > Any other objections to the series? Vincent marked 1, 3 and 4 as > reviewed. While patch 2 had some mild cosmetic concerns, I think the > version and how it treats SIS_PROP is fine as it is to keep it > functionally equivalent to !SIS_PROP and without adding too many > SIS_PROP checks. while testing your patchset and Aubrey one on top of tip, I'm facing some perf regression on my arm64 numa system on hackbench and reaim. The regression seems to comes from your patchset but i don't know which patch in particular yet hackbench -l 256000 -g 1 v5.10-rc7 + tip/sched/core 13,255(+/- 3.22%) with your patchset 15.368(+/- 2.74) -15.9% I'm also seeing perf regression on reaim but this one needs more investigation before confirming TBH, I was not expecting regressions. I'm running more test to find which patch is the culprit > > -- > Mel Gorman > SUSE Labs _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel