Commit 8c92606a authored by Andrey Ryabinin's avatar Andrey Ryabinin Committed by Peter Zijlstra
Browse files

sched/cpuacct: Make user/system times in cpuacct.stat more precise 



cpuacct.stat shows user time based on raw random precision tick
based counters. Use cputime_addjust() to scale these values against the
total runtime accounted by the scheduler, like we already do
for user/system times in /proc/<pid>/stat.

Signed-off-by: default avatarAndrey Ryabinin <arbn@yandex-team.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: default avatarDaniel Jordan <daniel.m.jordan@oracle.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Link: https://lore.kernel.org/r/20211115164607.23784-4-arbn@yandex-team.com
parent dd02d423

kernel/sched/cpuacct.c

+15 −10
Original line number Diff line number Diff line
@@ -261,25 +261,30 @@ static int cpuacct_all_seq_show(struct seq_file *m, void *V) 
static int cpuacct_stats_show(struct seq_file *sf, void *v)

{

	struct cpuacct *ca = css_ca(seq_css(sf));

	s64 val[CPUACCT_STAT_NSTATS];

	struct task_cputime cputime;

	u64 val[CPUACCT_STAT_NSTATS];

	int cpu;

	int stat;



	memset(val, 0, sizeof(val));

	memset(&cputime, 0, sizeof(cputime));

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

	}



	cputime_adjust(&cputime, &seq_css(sf)->cgroup->prev_cputime,

		&val[CPUACCT_STAT_USER], &val[CPUACCT_STAT_SYSTEM]);



	for (stat = 0; stat < CPUACCT_STAT_NSTATS; stat++) {

		seq_printf(sf, "%s %lld\n",

			   cpuacct_stat_desc[stat],

			   (long long)nsec_to_clock_t(val[stat]));

		seq_printf(sf, "%s %llu\n", cpuacct_stat_desc[stat],

			nsec_to_clock_t(val[stat]));

	}



	return 0;