Re: [PATCH v2 0/3] perf,x86: add Intel RAPL PMU support

[Arnaldo Carvalho de Melo]

Em Wed, Oct 16, 2013 at 03:13:54PM +0200, Stephane Eranian escreveu:
> On Wed, Oct 16, 2013 at 2:46 PM, Ingo Molnar <mingo@xxxxxxxxxx> wrote:
> > We should also tell user-space that the unit of this counter is 'Joule'.
> >
> > Then things like:
> >
> >         perf stat -a -e power/* sleep 1
> >
> > would output, without knowing any RAPL details:
> >
> >             0.20619 Joule    power/energy-core
> >             2.42151 Joule    power/energy-pkg
> >
> Not sure there is already some support for this in perf stat. Arnaldo?

Nope, there is not, we would have to have some table somewhere with
"event-regexp: unit-string"

> If not that we need another sysfs file to export the unit. Another
> possibility is for perf stat to recognize the power/* and extract the
> unit from the event name. In my example power/joules-cores -> joules.

I.e. you would be encoding the counter unit as the suffix, might as well
call it "power/cores.joules" and use the dot as the separator for the
unit, but would be just a compact form to encode the counter->unit
table.

- Arnaldo
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