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

[Stephane Eranian]

On Wed, Oct 16, 2013 at 7:53 PM, Arnaldo Carvalho de Melo
<acme@xxxxxxxxxx> wrote:
> 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.
>
May be easier to add a sysfs entry with the unit to display.
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