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=-10.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=unavailable 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 A9839C4338F for ; Tue, 24 Aug 2021 11:30:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8859561184 for ; Tue, 24 Aug 2021 11:30:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236554AbhHXLam (ORCPT ); Tue, 24 Aug 2021 07:30:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35442 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235509AbhHXLak (ORCPT ); Tue, 24 Aug 2021 07:30:40 -0400 Received: from mail-pg1-x52c.google.com (mail-pg1-x52c.google.com [IPv6:2607:f8b0:4864:20::52c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 71B38C061757; Tue, 24 Aug 2021 04:29:56 -0700 (PDT) Received: by mail-pg1-x52c.google.com with SMTP id e7so19481435pgk.2; Tue, 24 Aug 2021 04:29:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=bsdgxIajsLvyVXx8QcFLfpT4UU3Qk94eKj1fu3Cdnaw=; b=J3ekKR18f6EpfnXFMKOiNoVDKE9K1qm0B5w7HFPwkzzrx5ce4ur4+XKjQgQrZdPVMA G5K5pEmPRVvdao/miOhvVJZzh6bCUBCwlfZNxPbyBbqjXFD1bKujeeZMCFREoLGGvmOl Z9MUtkgK51i2bo2Z55z/2IcXruBsWAgdnRv7csJezdK0ptRz6VdjYdSMTMZd1YMOyv6Q 295iUMfB12hYVzU25/413G7K0LghwJeaB46gZ5TboN+IC5zue6/5Dwd1SlNCznVFW9ko ix7/6NKCm+uB9vfWN2jPzQcfl8frL4wj9V5em1vDcszreDGNUr9K0eYhJKvIQg4mHMF0 3wLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=bsdgxIajsLvyVXx8QcFLfpT4UU3Qk94eKj1fu3Cdnaw=; b=Qxi1FPORavyNmt+RGT7Ct9py8LSseUVXA4bkOj0I/SC1W+WiNhegMhrRHu/VPW/yGj SjsL+gayjAceZdqzcQY6Dd3vuiZlprh+LzYuZs+WgXBA61neVqXjbDkSYOJenuiNDTNq p+c4PPdjtlu1KZuWGx1M6kjplcwgpcxtDXrYjRqmZfHq+rHfxB/dBw1Yd6DHLOQYkkWs ngkCilZ+XWwdch8Gxl81ZMV650VXZJnS8Qb1LeX0dNeIaXe08x+nOFzZAaxAhCOAVoFl Lx0PfP10sWFEkDD0bemMBO0TwQNhiItO2ET8y8Bevzp13WyxowsCVfzQW9LTUWJfyby3 /QFw== X-Gm-Message-State: AOAM531w1Hs8L7BPKkqkGW0eS6tfWAgom+dfABBZ7JnTrUoOkI9qfXpt xfVF8hJLcj6zyNHGRikMYwrFnxch9IDpIxfm X-Google-Smtp-Source: ABdhPJxZDe0Vn3bPAlX2uXZ17tJveBRj/XZO7Fu54rsB2WSLFgimsBcrrKKeI7tXQt3Fyo9qhZrRCQ== X-Received: by 2002:a05:6a00:150d:b0:3e2:13fc:dd2b with SMTP id q13-20020a056a00150d00b003e213fcdd2bmr38430712pfu.71.1629804595943; Tue, 24 Aug 2021 04:29:55 -0700 (PDT) Received: from localhost.localdomain ([45.77.24.247]) by smtp.gmail.com with ESMTPSA id on15sm2128732pjb.19.2021.08.24.04.29.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 24 Aug 2021 04:29:55 -0700 (PDT) From: Yafang Shao To: mingo@redhat.com, peterz@infradead.org, mgorman@suse.de, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, bristot@redhat.com, achaiken@aurora.tech Cc: lkp@intel.com, linux-kernel@vger.kernel.org, linux-rt-users@vger.kernel.org, Yafang Shao Subject: [PATCH v3 0/7] sched: support schedstats for RT sched class Date: Tue, 24 Aug 2021 11:29:39 +0000 Message-Id: <20210824112946.9324-1-laoar.shao@gmail.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Ingo, Peter, This feature is useful to trace the sched details of RT tasks. Hopefully you can give some feedback on it. We want to measure the latency of RT tasks in our production environment with schedstats facility, but currently schedstats is only supported for fair sched class. In order to support if for other sched classes, we should make it independent of fair sched class. The struct sched_statistics is the schedular statistics of a task_struct or a task_group, both of which are independent of sched class. So we can move struct sched_statistics into struct task_struct and struct task_group to achieve the goal. After the patchset, schestats are orgnized as follows, struct task_struct { ... struct sched_statistics statistics; ... struct sched_entity *se; struct sched_rt_entity *rt; ... }; struct task_group { |---> stats[0] : of CPU0 ... | struct sched_statistics **stats; --|---> stats[1] : of CPU1 ... | |---> stats[n] : of CPUn #ifdef CONFIG_FAIR_GROUP_SCHED struct sched_entity **se; #endif #ifdef CONFIG_RT_GROUP_SCHED struct sched_rt_entity **rt_se; #endif ... }; The sched_statistics members may be frequently modified when schedstats is enabled, in order to avoid impacting on random data which may in the same cacheline with them, the struct sched_statistics is defined as cacheline aligned. Then we can use schedstats to trace RT tasks as well, for example, Interface File task schedstats : /proc/[pid]/sched group schedstats: /proc/sched_debug tracepoints : sched:sched_stat_{runtime, wait, sleep, iowait, blocked} As PATCH #2 and #3 changes the core struct in the scheduler, so I did 'perf bench sched pipe' to measure the sched performance before and after the change, suggested by Mel. Below is the data, which are all in usecs/op. Before After kernel.sched_schedstats=0 ~5.6 ~5.6 kernel.sched_schedstats=1 ~5.7 ~5.7 [These data is a little difference with the prev version, that is because my old test machine is destroyed so I have to use a new different test machine.] No obvious difference after the change. Changes Since v2: - Fixes the output format in /proc/[pid]/sched - Rebase it on the latest code - Redo the performance test Changes since v1: - Fix the build failure reported by kernel test robot. - Add the performance data with 'perf bench sched pipe', suggested by Mel. - Make the struct sched_statistics cacheline aligned. - Introduce task block time in schedstats Changes since RFC: - improvement of schedstats helpers, per Mel. - make struct schedstats independent of fair sched class Yafang Shao (7): sched, fair: use __schedstat_set() in set_next_entity() sched: make struct sched_statistics independent of fair sched class sched: make schedstats helpers independent of fair sched class sched: make the output of schedstats independent of fair sched class sched: introduce task block time in schedstats sched, rt: support sched_stat_runtime tracepoint for RT sched class sched, rt: support schedstats for RT sched class include/linux/sched.h | 7 +- kernel/sched/core.c | 24 +++-- kernel/sched/deadline.c | 4 +- kernel/sched/debug.c | 136 +++++++++++++++---------- kernel/sched/fair.c | 210 ++++++++++++++++----------------------- kernel/sched/rt.c | 147 ++++++++++++++++++++++++++- kernel/sched/sched.h | 3 + kernel/sched/stats.c | 104 +++++++++++++++++++ kernel/sched/stats.h | 89 +++++++++++++++++ kernel/sched/stop_task.c | 4 +- 10 files changed, 531 insertions(+), 197 deletions(-) -- 2.18.2