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 85179ECDFB1 for ; Tue, 17 Jul 2018 03:29:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0ECF020877 for ; Tue, 17 Jul 2018 03:29:41 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0ECF020877 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 S1730161AbeGQD7y (ORCPT ); Mon, 16 Jul 2018 23:59:54 -0400 Received: from out30-131.freemail.mail.aliyun.com ([115.124.30.131]:48975 "EHLO out30-131.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729927AbeGQD7y (ORCPT ); Mon, 16 Jul 2018 23:59:54 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R861e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01355;MF=yun.wang@linux.alibaba.com;NM=1;PH=DS;RN=3;SR=0;TI=SMTPD_---0T4mHunT_1531798121; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0T4mHunT_1531798121) by smtp.aliyun-inc.com(127.0.0.1); Tue, 17 Jul 2018 11:28:41 +0800 Subject: Re: [PATCH v2] 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: <4abd1bae-dc1e-3a13-40d4-c6c73ecc07b1@linux.alibaba.com> Date: Tue, 17 Jul 2018 11:28:40 +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: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, folks On 2018/7/4 上午11:27, 王贇 wrote: > 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. Any comments please? Regards, Michael Wang > > Signed-off-by: Michael Wang > --- > > Since v1: >   Use schedstat_val to avoid compile error >   Check and skip root_task_group > >  kernel/sched/core.c | 8 ++++++++ >  1 file changed, 8 insertions(+) > > diff --git a/kernel/sched/core.c b/kernel/sched/core.c > index 78d8fac..80ab995 100644 > --- a/kernel/sched/core.c > +++ b/kernel/sched/core.c > @@ -6781,6 +6781,8 @@ static int __cfs_schedulable(struct task_group *tg, u64 period, u64 quota) > >  static int cpu_cfs_stat_show(struct seq_file *sf, void *v) >  { > +    int i; > +    u64 ws = 0; >      struct task_group *tg = css_tg(seq_css(sf)); >      struct cfs_bandwidth *cfs_b = &tg->cfs_bandwidth; > > @@ -6788,6 +6790,12 @@ 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) { > +        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 */