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From: Daniel Jordan <daniel.m.jordan@oracle.com>
To: Andrey Ryabinin <arbn@yandex-team.com>
Cc: Tejun Heo <tj@kernel.org>, Zefan Li <lizefan.x@bytedance.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	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>,
	cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
	bharata@linux.vnet.ibm.com, boris@bur.io, stable@vger.kernel.org
Subject: Re: [PATCH v2 4/5] sched/cpuacct: fix user/system in shown cpuacct.usage*
Date: Fri, 10 Sep 2021 15:03:26 -0400	[thread overview]
Message-ID: <20210910190326.nwv7kktt42nucoit@oracle.com> (raw)
In-Reply-To: <20210820094005.20596-4-arbn@yandex-team.com>

On Fri, Aug 20, 2021 at 12:40:04PM +0300, Andrey Ryabinin wrote:
> cpuacct has 2 different ways of accounting and showing user
> and system times.
> 
> The first one uses cpuacct_account_field() to account times
> and cpuacct.stat file to expose them. And this one seems to work ok.
> 
> The second one is uses cpuacct_charge() function for accounting and
> set of cpuacct.usage* files to show times. Despite some attempts to
> fix it in the past it still doesn't work. Sometimes while running KVM
> guest the cpuacct_charge() accounts most of the guest time as
> system time. This doesn't match with user&system times shown in
> cpuacct.stat or proc/<pid>/stat.
> 
> Demonstration:
>  # git clone https://github.com/aryabinin/kvmsample
>  # make
>  # mkdir /sys/fs/cgroup/cpuacct/test
>  # echo $$ > /sys/fs/cgroup/cpuacct/test/tasks
>  # ./kvmsample &
>  # for i in {1..5}; do cat /sys/fs/cgroup/cpuacct/test/cpuacct.usage_sys; sleep 1; done
>  1976535645
>  2979839428
>  3979832704
>  4983603153
>  5983604157

Thanks for expanding on this, and fixing broken cpuacct_charge.

For the series,
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>

  reply	other threads:[~2021-09-10 19:04 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-17 12:00 [PATCH 1/4] cputime,cpuacct: Include guest time in user time in cpuacct.stat Andrey Ryabinin
2021-02-17 12:00 ` [PATCH 2/4] cgroup: Fix 'usage_usec' time in root's cpu.stat Andrey Ryabinin
2021-03-17 22:13   ` Daniel Jordan
2021-02-17 12:00 ` [PATCH 3/4] sched/cpuacct: fix user/system in shown cpuacct.usage* Andrey Ryabinin
2021-03-17 22:22   ` Daniel Jordan
2021-08-20  9:37     ` Andrey Ryabinin
2021-02-17 12:00 ` [PATCH 4/4] sched/cpuacct: Make user/system times in cpuacct.stat more precise Andrey Ryabinin
2021-03-17 22:25   ` Daniel Jordan
2021-03-17 22:09 ` [PATCH 1/4] cputime,cpuacct: Include guest time in user time in cpuacct.stat Daniel Jordan
2021-08-20  9:37   ` Andrey Ryabinin
2021-08-20  9:40 ` [PATCH v2 1/5] cputime, cpuacct: " Andrey Ryabinin
2021-08-20  9:40   ` [PATCH v2 2/5] cpuacct: convert BUG_ON() to WARN_ON_ONCE() Andrey Ryabinin
2021-08-20  9:40   ` [PATCH v2 3/5] cgroup: Fix 'usage_usec' time in root's cpu.stat Andrey Ryabinin
2021-08-20  9:40   ` [PATCH v2 4/5] sched/cpuacct: fix user/system in shown cpuacct.usage* Andrey Ryabinin
2021-09-10 19:03     ` Daniel Jordan [this message]
2021-08-20  9:40   ` [PATCH v2 5/5] sched/cpuacct: Make user/system times in cpuacct.stat more precise Andrey Ryabinin
2021-09-07 17:19   ` [PATCH v2 1/5] cputime, cpuacct: Include guest time in user time in cpuacct.stat Tejun Heo

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