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=-0.6 required=3.0 tests=FROM_EXCESS_BASE64, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY, URIBL_BLOCKED autolearn=ham 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 297F7ECDE5F for ; Mon, 23 Jul 2018 13:31:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9621920856 for ; Mon, 23 Jul 2018 13:31:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9621920856 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388245AbeGWOdE (ORCPT ); Mon, 23 Jul 2018 10:33:04 -0400 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:36443 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388083AbeGWOdE (ORCPT ); Mon, 23 Jul 2018 10:33:04 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R721e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01f04452;MF=yun.wang@linux.alibaba.com;NM=1;PH=DS;RN=3;SR=0;TI=SMTPD_---0T5AWNMp_1532352703; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0T5AWNMp_1532352703) by smtp.aliyun-inc.com(127.0.0.1); Mon, 23 Jul 2018 21:31:44 +0800 Subject: [PATCH v3] tg: show the sum wait time of an task group From: =?UTF-8?B?546L6LSH?= To: Ingo Molnar , Peter Zijlstra , linux-kernel@vger.kernel.org References: <5c4c978d-e8fb-4bcb-b942-3c6d3dcfc13e@linux.alibaba.com> Message-ID: <336c292e-be0a-f03d-d992-9f55b969ed12@linux.alibaba.com> Date: Mon, 23 Jul 2018 21:31:26 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:52.0) Gecko/20100101 Thunderbird/52.8.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Although we can rely on cpuacct to present the cpu usage of task group, it is hard to tell how intense the competition is between these groups on cpu resources. Monitoring the wait time of each process or sched_debug could cost too much, and there is no good way to accurately represent the conflict with these info, we need the wait time on group dimension. Thus we introduced group's wait_sum represent the conflict between task groups, which is simply sum the wait time of group's cfs_rq. The 'cpu.stat' is modified to show the statistic, like: nr_periods 0 nr_throttled 0 throttled_time 0 wait_sum 2035098795584 Now we can monitor the changing on wait_sum to tell how suffering a task group is in the fight of cpu resources. For example: (wait_sum - last_wait_sum) * 100 / (nr_cpu * period_ns) == X% means the task group paid X percentage of period on waiting for the cpu. Signed-off-by: Michael Wang --- Since v2: Declare variables inside branch (From Peter). kernel/sched/core.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 78d8fac..2a7bb7c 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6788,6 +6788,15 @@ static int cpu_cfs_stat_show(struct seq_file *sf, void *v) seq_printf(sf, "nr_throttled %d\n", cfs_b->nr_throttled); seq_printf(sf, "throttled_time %llu\n", cfs_b->throttled_time); + if (schedstat_enabled() && tg != &root_task_group) { + int i; + u64 ws = 0; + + for_each_possible_cpu(i) + ws += schedstat_val(tg->se[i]->statistics.wait_sum); + seq_printf(sf, "wait_sum %llu\n", ws); + } + return 0; } #endif /* CONFIG_CFS_BANDWIDTH */ -- 1.8.3.1