Re: recording rapl/power events

[Adrien BAK <adrien.bak@metascale.org>]

hi  Namhyung,

yes it seems. However, when I run what you suggest, I get the following :

perf record -a -e '{cycles,power/energy-pkg/}:S' sleep 1
Error:
The sys_perf_event_open() syscall returned with 22 (Invalid argument) 
for event (power/energy-pkg/).
/bin/dmesg may provide additional information.
No CONFIG_PERF_EVENTS=y kernel support configured?

Once again, I'm pretty sure my kernel is correctly configured, as I can 
get power measurement using perf stat. Is this a bug somewhere ? Can you 
confirm that this works for you and that I should investigate what can 
go wrong with my system ?

A.


On 25/04/2014 17:29, Namhyung Kim wrote:
> Hi Andi,
>
> On Tue, 22 Apr 2014 03:17:56 -0700, Andi Kleen wrote:
>> Adrien BAK <adrien.bak@metascale.org> writes:
>>> This looks promising, although I couldn't find any useful
>>> documentation on this. Do you know if the perf userland tool allows
>>> for this kind of slave-sampling or if I have to build my own tool
>>> around the perf_event API ?
>> perf record supports it (with :S), but none of the reporting tools
>> unfortunately.
> It seems it's what --group option of perf report is for?
>
>    $ perf record -e '{cycles,power/energy-pkg/}:S' -a sleep 1
>
>    $ perf report --group --stdio
>
>
> Thanks,
> Namhyung
>
>> However keep in mind that very rapid sampling of RAPL is not
>> likely to give useful results. The data only really makes
>> sense over longer intervals.
>>
>> -Andi
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