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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7345C001DF for ; Fri, 20 Oct 2023 01:27:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1346811AbjJTB1z (ORCPT ); Thu, 19 Oct 2023 21:27:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58010 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346768AbjJTB1y (ORCPT ); Thu, 19 Oct 2023 21:27:54 -0400 Received: from smtp-fw-33001.amazon.com (smtp-fw-33001.amazon.com [207.171.190.10]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5E8C3116 for ; Thu, 19 Oct 2023 18:27:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1697765274; x=1729301274; h=message-id:date:mime-version:to:from:cc:subject: content-transfer-encoding; bh=gRHIWGBX70z/DJmBCO4m5ERrAqpwWSa9w8RtpF/7jLg=; b=kc1wwwRgpNhdcMZCQ96mZX9YpMOOxVv5iby9yzj3ziBiRcBE7zYS0cp7 4gXrDWgo0iUN2EKEjS9VlmouE4Rd51f12t3VgGvSpbApDxBQPkAuC1cP3 MTPmsz94ED2ob86UKwCXYZjHTTVA95Zo1k8mex8UJBhYf9Z1dEuNXfyzo A=; X-IronPort-AV: E=Sophos;i="6.03,238,1694736000"; d="scan'208";a="309451795" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO email-inbound-relay-iad-1e-m6i4x-6e7a78d7.us-east-1.amazon.com) ([10.43.8.6]) by smtp-border-fw-33001.sea14.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Oct 2023 01:27:47 +0000 Received: from smtpout.prod.us-east-1.prod.farcaster.email.amazon.dev (iad7-ws-svc-p70-lb3-vlan2.iad.amazon.com [10.32.235.34]) by email-inbound-relay-iad-1e-m6i4x-6e7a78d7.us-east-1.amazon.com (Postfix) with ESMTPS id 7387A88416; Fri, 20 Oct 2023 01:27:45 +0000 (UTC) Received: from EX19MTAUEB002.ant.amazon.com [10.0.29.78:56613] by smtpin.naws.us-east-1.prod.farcaster.email.amazon.dev [10.0.62.238:2525] with esmtp (Farcaster) id bfc3f018-7291-43d7-ab6c-b10fc8d61a6a; Fri, 20 Oct 2023 01:27:44 +0000 (UTC) X-Farcaster-Flow-ID: bfc3f018-7291-43d7-ab6c-b10fc8d61a6a Received: from EX19D028UEC003.ant.amazon.com (10.252.137.159) by EX19MTAUEB002.ant.amazon.com (10.252.135.47) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.37; Fri, 20 Oct 2023 01:27:40 +0000 Received: from [10.95.211.45] (10.95.211.45) by EX19D028UEC003.ant.amazon.com (10.252.137.159) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.37; Fri, 20 Oct 2023 01:27:39 +0000 Message-ID: <97397e8d-f447-4cf7-84a1-070989d0a7fd@amazon.com> Date: Thu, 19 Oct 2023 21:27:37 -0400 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Content-Language: en-US To: "stable@vger.kernel.org" , Greg KH , "sashal@kernel.org" From: Luiz Capitulino CC: <42.hyeyoo@gmail.com> Subject: [6.1] Please apply cc6003916ed46d7a67d91ee32de0f9138047d55f Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.95.211.45] X-ClientProxiedBy: EX19D044UWA001.ant.amazon.com (10.13.139.100) To EX19D028UEC003.ant.amazon.com (10.252.137.159) Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org Hi, As reported before[1], we found another regression in 6.1 when doing performance comparisons with 5.10. This one is caused by CONFIG_DEBUG_PREEMPT being enabled by default by the following upstream commit if you have the right config dependencies enabled (commit is introduced in v5.16-rc1): """ commit c597bfddc9e9e8a63817252b67c3ca0e544ace26 Author: Frederic Weisbecker Date: Tue Sep 14 12:31:34 2021 +0200 sched: Provide Kconfig support for default dynamic preempt mode """ We found up to 8% performance improvement with CONFIG_DEBUG_PREEMPT disabled in different perf benchmarks (including UnixBench process creation and redis). The root cause is explained in the commit log below which is merged in 6.3 and applies (almost) clealy on 6.1.59. """ commit cc6003916ed46d7a67d91ee32de0f9138047d55f Author: Hyeonggon Yoo <42.hyeyoo@gmail.com> Date: Sat Jan 21 12:39:42 2023 +0900 lib/Kconfig.debug: do not enable DEBUG_PREEMPT by default In workloads where this_cpu operations are frequently performed, enabling DEBUG_PREEMPT may result in significant increase in runtime overhead due to frequent invocation of __this_cpu_preempt_check() function. This can be demonstrated through benchmarks such as hackbench where this configuration results in a 10% reduction in performance, primarily due to the added overhead within memcg charging path. """ [1] https://lore.kernel.org/stable/010edf5a-453d-4c98-9c07-12e75d3f983c@amazon.com/