linux-kernel - Re: [PATCH 4/4] sched/cpuacct: Make user/system times in cpuacct.stat more precise

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Date:   Wed, 17 Mar 2021 18:25:13 -0400
From:   Daniel Jordan <daniel.m.jordan@...cle.com>
To:     Andrey Ryabinin <arbn@...dex-team.com>,
        Ingo Molnar <mingo@...hat.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Juri Lelli <juri.lelli@...hat.com>,
        Vincent Guittot <vincent.guittot@...aro.org>,
        Tejun Heo <tj@...nel.org>, Zefan Li <lizefan.x@...edance.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Dietmar Eggemann <dietmar.eggemann@....com>,
        Steven Rostedt <rostedt@...dmis.org>,
        Ben Segall <bsegall@...gle.com>, Mel Gorman <mgorman@...e.de>,
        Daniel Bristot de Oliveira <bristot@...hat.com>
Cc:     Boris Burkov <boris@....io>,
        Bharata B Rao <bharata@...ux.vnet.ibm.com>,
        cgroups@...r.kernel.org, linux-kernel@...r.kernel.org,
        Andrey Ryabinin <arbn@...dex-team.com>
Subject: Re: [PATCH 4/4] sched/cpuacct: Make user/system times in
 cpuacct.stat more precise

Andrey Ryabinin <arbn@...dex-team.com> writes:
>  static int cpuacct_stats_show(struct seq_file *sf, void *v)
>  {
        ...
>  	for_each_possible_cpu(cpu) {
>  		u64 *cpustat = per_cpu_ptr(ca->cpustat, cpu)->cpustat;
>  
> -		val[CPUACCT_STAT_USER] += cpustat[CPUTIME_USER];
> -		val[CPUACCT_STAT_USER] += cpustat[CPUTIME_NICE];
> -		val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SYSTEM];
> -		val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_IRQ];
> -		val[CPUACCT_STAT_SYSTEM] += cpustat[CPUTIME_SOFTIRQ];
> +		cputime.utime += cpustat[CPUTIME_USER];
> +		cputime.utime += cpustat[CPUTIME_NICE];
> +		cputime.stime += cpustat[CPUTIME_SYSTEM];
> +		cputime.stime += cpustat[CPUTIME_IRQ];
> +		cputime.stime += cpustat[CPUTIME_SOFTIRQ];
> +
> +		cputime.sum_exec_runtime += this_cpu_read(*ca->cpuusage);
>  	}

                cputime.sum_exec_runtime += *per_cpu_ptr(ca->cpuusage, cpu);

Or the stats can all be 0...