Re: [RFC][PATCH] sched: cpuacct: Track cpuusage per cpu frequency

From: Balbir Singh
Date: Mon Apr 05 2010 - 22:16:16 EST

* menage@xxxxxxxxxx <menage@xxxxxxxxxx> [2010-04-05 12:52:57]:

> On Mon, Apr 5, 2010 at 12:33 PM, Mike Chan <mike@xxxxxxxxxxx> wrote:
> > New file: cpuacct.cpufreq when CONFIG_CPU_FREQ_STATS is enabled.
> >
> > cpuacct.cpufreq accounts for cpu time per-cpu frequency, time is exported
> > in nano-seconds
> Can you clarify the wording of this (and describe it in the relevant
> Documentation/... file)? It's not clear.
> From the code, it appears that the file reports a breakdown of how
> much CPU time the cgroup has been consuming at each different CPU
> frequency level. If so, then you probably want to reword the
> description to avoid "per-cpu", since that makes it sounds as though
> it's reporting something, well, "per CPU".
> Also, what's the motivation here? If it's for power monitoring
> purposes, might it be simpler to just report a single number, that's
> the integral of the CPU usage by frequency index (i.e. calculated from
> the same information that this patch is already gathering in
> cpuacct_charge()) rather than dumping a whole table on userspace?

As utilization increases, won't the integral quickly overflow? BTW,
Mike have you looked at the scaled accounting infrastructure we have
in taskstats?

Three Cheers,
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at