linux-kernel - Re: [PATCH v2 2/4] numa: append per-node execution time in cpu.numa

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Date:   Mon, 22 Jul 2019 10:36:45 +0800
From:   王贇 <yun.wang@...ux.alibaba.com>
To:     Michal Koutný <mkoutny@...e.com>
Cc:     hannes@...xchg.org, vdavydov.dev@...il.com,
        Peter Zijlstra <peterz@...radead.org>, mhocko@...nel.org,
        Ingo Molnar <mingo@...hat.com>, keescook@...omium.org,
        mcgrof@...nel.org, linux-mm@...ck.org,
        Hillf Danton <hdanton@...a.com>, cgroups@...r.kernel.org,
        linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/4] numa: append per-node execution time in
 cpu.numa_stat



On 2019/7/20 上午12:39, Michal Koutný wrote:
> On Tue, Jul 16, 2019 at 11:40:35AM +0800, 王贇  <yun.wang@...ux.alibaba.com> wrote:
>> By doing 'cat /sys/fs/cgroup/cpu/CGROUP_PATH/cpu.numa_stat', we see new
>> output line heading with 'exectime', like:
>>
>>   exectime 311900 407166
> What you present are times aggregated over CPUs in the NUMA nodes, this
> seems a bit lossy interface. 
> 
> Despite you the aggregated information is sufficient for your
> monitoring, I think it's worth providing the information with the
> original granularity.

As Peter suggested previously, kernel do not report jiffies to user anymore
and 'ms' could be better, I guess usually we care about how much the percentage
is on a particular node?

> 
> Note that cpuacct v1 controller used to report such percpu runtime
> stats. The v2 implementation would rather build upon the rstat API.

Support cgroup v2 is on the plan :-) let's mark this as todo currently,
i suppose they may not share the same piece of code.

Regards,
Michael Wang

> 
> Michal
>