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From: Tejun Heo <tj@kernel.org>
To: Josh Don <joshdon@google.com>
Cc: Ingo Molnar <mingo@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Juri Lelli <juri.lelli@redhat.com>,
	Vincent Guittot <vincent.guittot@linaro.org>,
	Dietmar Eggemann <dietmar.eggemann@arm.com>,
	Steven Rostedt <rostedt@goodmis.org>,
	Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Valentin Schneider <vschneid@redhat.com>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Cruz Zhao <CruzZhao@linux.alibaba.com>
Subject: Re: [PATCH] sched/core: add forced idle accounting for cgroups
Date: Fri, 20 May 2022 08:43:47 -1000	[thread overview]
Message-ID: <YofhY8kcTrQOs2iF@slm.duckdns.org> (raw)
In-Reply-To: <CABk29Nv=J_ZUnDTkRhwdQop=REr_XDGjJxn_zVy4kBqwx8K57w@mail.gmail.com>

Hello,

Sorry about late reply and thanks for the ping. I missed this one.

On Fri, May 13, 2022 at 12:23:16PM -0700, Josh Don wrote:
> Yea, that's right, this doesn't require the cpu controller to be
> enabled. Are you suggesting to add a new field to cgroup_base_stat?

Yes, that's what I meant. I think it'd fit there better.

> One other weird artifact of collecting forceidle time is that a cpu
> may account it on behalf of its hyperthread sibling. Currently, the
> core rstat code always accounts to the current cpu's percpu rstat
> field. I can add an accounting function to support writes to a
> different cpu's field, in order to make sure that the per-cpu totals
> are correct (the forceidle accounting code holds rq->__lock, which
> protects all HT siblings of a core). percpu totals aren't currently
> exported in cgroup v2, but this is useful information that we'll
> consume, so it would be nice to keep it accurate.

Sure, as long as it doesn't incur overhead when not used.

Thanks.

-- 
tejun

  reply	other threads:[~2022-05-20 18:43 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-05-13  0:54 [PATCH] sched/core: add forced idle accounting for cgroups Josh Don
2022-05-13  2:58 ` Tejun Heo
2022-05-13 19:23   ` Josh Don
2022-05-20 18:43     ` Tejun Heo [this message]
2022-05-20 23:09       ` Josh Don
2022-05-13  6:34 ` kernel test robot
2022-05-13  9:09 ` kernel test robot
2022-05-13 11:33 ` kernel test robot

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