From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-13.3 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 16B237D2EF for ; Thu, 27 Jun 2019 19:49:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726472AbfF0Ttj (ORCPT ); Thu, 27 Jun 2019 15:49:39 -0400 Received: from mail-oi1-f180.google.com ([209.85.167.180]:35321 "EHLO mail-oi1-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726463AbfF0Ttj (ORCPT ); Thu, 27 Jun 2019 15:49:39 -0400 Received: by mail-oi1-f180.google.com with SMTP id a127so2503694oii.2 for ; Thu, 27 Jun 2019 12:49:39 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=indeed.com; s=google; h=from:to:subject:date:message-id:in-reply-to:references; bh=AesOW3EmeuBjZTWgdRCKfU4DW0QAsRu61r3/LGTQTg8=; b=NCZODYSjpvpfxj59czkgru2M6MbuOf355ojoS6qv35oesf0ZPEKewPbzf8Q6hUTwNZ 63GC9qzntLhV3BXxzsA1wfMonAydRnckvGu7+Ty6+pC2zHJpo0wDteG4b3WNGiac6WEN get4j9BzPfJbNVLnEdYRJcAD/bpv4qOuVvgK4= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:in-reply-to :references; bh=AesOW3EmeuBjZTWgdRCKfU4DW0QAsRu61r3/LGTQTg8=; b=kSIK5Hzvucijifw1a3ZGQQSacQIh0M9194PY1hg/eV8YkyD83fGGKvS9X7FGLZJG2G KMnuDurMLwW519NyYWhTuc9WxwsAFGYw8GzjSfi7eZBvI8EISGda1WCtBV1EJACfUMkB n1AUmSxtNMaPdr24i+gOe05dBEOTNH28+06utBNVrDZ7cJmD4Xv2vru5WA0pjoSkjfNI OehWKLsivs6q2ENddnwD5TRIhwAz1bDnb1XxHCaeP4lkk/cI96cIeLfXQJV6egSh5RSY y5l70BTDWurRzsotXGWhYYMCA3hQA8Q6DHPFlRNKZnwk18S5+DEInPYh1CtzrDbAymOy Qq0w== X-Gm-Message-State: APjAAAUvJY0QmIHK6O8U7JlJBnYXHeIHqjwLmF/58mFnNmxXbYXaJ+qC oqgnT/j0qCrp57ne6OiYa/kowA== X-Google-Smtp-Source: APXvYqyVAP6KFgB2RBp3IQGLzuIHqYp8k5AhEcsIAc1tToG/shUzilO1cd2B6XGEl8mHP2WOzj0kvQ== X-Received: by 2002:aca:cfd0:: with SMTP id f199mr3076083oig.50.1561664978390; Thu, 27 Jun 2019 12:49:38 -0700 (PDT) Received: from cando.ausoff.indeed.net ([97.105.47.162]) by smtp.gmail.com with ESMTPSA id d200sm1148032oih.26.2019.06.27.12.49.37 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 27 Jun 2019 12:49:37 -0700 (PDT) From: Dave Chiluk To: Ben Segall , Pqhil Auld , Peter Oskolkov , Peter Zijlstra , Ingo Molnar , cgroups@vger.kernel.org, linux-kernel@vger.kernel.org, Brendan Gregg , Kyle Anderson , Gabriel Munos , John Hammond , Cong Wang , Jonathan Corbet , linux-doc@vger.kernel.org Subject: [PATCH v5 0/1] sched/fair: Fix low cpu usage with high throttling by removing expiration of cpu-local slices Date: Thu, 27 Jun 2019 14:49:29 -0500 Message-Id: <1561664970-1555-1-git-send-email-chiluk+linux@indeed.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1558121424-2914-1-git-send-email-chiluk+linux@indeed.com> References: <1558121424-2914-1-git-send-email-chiluk+linux@indeed.com> Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org Changelog v5 - Based on this comment from Ben Segall's comment on v4 > If the cost of taking this global lock across all cpus without a > ratelimit was somehow not a problem, I'd much prefer to just set > min_cfs_rq_runtime = 0. (Assuming it is, I definitely prefer the "lie > and sorta have 2x period 2x runtime" solution of removing expiration) I'm resubmitting my v3 patchset, with the requested changes. - Updated Commit log given review comments - Update sched-bwc.txt give my new understanding of the slack timer. Changelog v4 - Rewrote patchset around the concept of returning all of runtime_remaining when cfs_b nears the end of available quota. Changelog v3 - Reworked documentation to better describe behavior of slice expiration per feedback from Peter Oskolkov Changelog v2 - Fixed some checkpatch errors in the commit message.