From patchwork Thu Feb 15 18:07:07 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Philip Cox X-Patchwork-Id: 1899671 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=lists.ubuntu.com (client-ip=185.125.189.65; helo=lists.ubuntu.com; envelope-from=kernel-team-bounces@lists.ubuntu.com; receiver=patchwork.ozlabs.org) Received: from lists.ubuntu.com (lists.ubuntu.com [185.125.189.65]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4TbNPh1V9Lz23jD for ; Fri, 16 Feb 2024 05:09:43 +1100 (AEDT) Received: from localhost ([127.0.0.1] helo=lists.ubuntu.com) by lists.ubuntu.com with esmtp (Exim 4.86_2) (envelope-from ) id 1ragAk-0001zA-Ge; Thu, 15 Feb 2024 18:09:23 +0000 Received: from smtp-relay-internal-0.internal ([10.131.114.225] helo=smtp-relay-internal-0.canonical.com) by lists.ubuntu.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1ragAe-0001z0-Se for kernel-team@lists.ubuntu.com; Thu, 15 Feb 2024 18:09:17 +0000 Received: from mail-qk1-f197.google.com (mail-qk1-f197.google.com [209.85.222.197]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp-relay-internal-0.canonical.com (Postfix) with ESMTPS id 96B803F186 for ; Thu, 15 Feb 2024 18:09:16 +0000 (UTC) Received: by mail-qk1-f197.google.com with SMTP id af79cd13be357-78315f41c6cso160971685a.1 for ; Thu, 15 Feb 2024 10:09:16 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708020554; x=1708625354; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=V4NHX2ZYllR4kCWFqmguiKKOs/7Vqcfu3ikPya02ZJo=; b=HbhLH2e+dx7py6mpgyLmK+9MzgVWQMRSEmDpPtancutdZ8UZK+uLAmfSrtpltMnuNp f35aO4e1CXLpfvwnbQUeBn+NOcq8OFCs6yBJpzqmThxoB5b8XQz9B6nuaP3CYh1UQpff emFMZOxtKkEBB6YsCW8zMXHOHR03CsNYMZPBi5Ej78Pnxb58OPWH5hdngUp8Q0wYcBG5 2SLT50uDSXDJ7RvwApB2ry+9QRsxBrQZI1QicMSZgfg47G8B6DIn38+T0tht7JKrq/m8 6CMBkHJTfoWZB8AZmYcj/y4MUl0dDbK/qnUc241WAOpU1wVZdUGxfXul8IWaZ5FVX102 xfBA== X-Gm-Message-State: AOJu0Yxjftwwg6HQ5Xh80KT8Xkf2ARUc0MTzrq4jb574Gibvt57bs55a X97s6kfGlUi2Tm0qiD45LjTu3DIxyteh2F0mutbPdp29IM32Hb83mPG6JuYwiogTt3liukd/pk0 f1AwDd/Z93vY6TBuICHHyEX1jodCUcftRuHm1mCKaN8vQsc7Jf5P9sSbKHCZFItqXFE7xMuHjiM rNTDUcfdX/yw== X-Received: by 2002:a05:620a:a04:b0:787:29cc:54bc with SMTP id i4-20020a05620a0a0400b0078729cc54bcmr2505542qka.65.1708020554121; Thu, 15 Feb 2024 10:09:14 -0800 (PST) X-Google-Smtp-Source: AGHT+IFHiOQ6AkRPuRfCWVEsPx1n75ikKF6HHB3qEJqEF+Q5uUd2bAGCjHpH8Dv3inYFpymlOEQ+Tg== X-Received: by 2002:a05:620a:a04:b0:787:29cc:54bc with SMTP id i4-20020a05620a0a0400b0078729cc54bcmr2505528qka.65.1708020553853; Thu, 15 Feb 2024 10:09:13 -0800 (PST) Received: from cox.home.arpa ([108.175.227.176]) by smtp.gmail.com with ESMTPSA id b19-20020a05620a0cd300b007840a08a097sm803313qkj.76.2024.02.15.10.09.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Feb 2024 10:09:12 -0800 (PST) From: Philip Cox To: kernel-team@lists.ubuntu.com Subject: [SRU][jammy][PATCH 0/1] performance: Scheduler: Improve cache bouncing on tg->load_avg Date: Thu, 15 Feb 2024 13:07:07 -0500 Message-Id: <20240215180708.891086-1-philip.cox@canonical.com> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 X-BeenThere: kernel-team@lists.ubuntu.com X-Mailman-Version: 2.1.20 Precedence: list List-Id: Kernel team discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: kernel-team-bounces@lists.ubuntu.com Sender: "kernel-team" BugLink: BugLink: https://bugs.launchpad.net/bugs/2053251 SRU Justification: [Impact] On high core count systems, the updating of the load average can happen so often that it impacts performance. [Fix] Reduce the updating of the load average to at most once per millisecond. [Test Plan] I have tested this patch, as has Intel. [Where problems could occur] The risk for regression is low as it is a fairly targetted change, and is just reducing the number of times that the load average is updated. Acked-by: Stefan Bader Acked-by: Manuel Diewald --- Aaron Lu (1): sched/fair: Ratelimit update to tg->load_avg kernel/sched/fair.c | 13 ++++++++++++- kernel/sched/sched.h | 1 + 2 files changed, 13 insertions(+), 1 deletion(-)