Re: recording rapl/power events

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

On 21/04/2014 23:07, Vince Weaver wrote:
> On Mon, 21 Apr 2014, Adrien BAK wrote:
>
>> However, it seems that I can't record a sequence of power events :
>>
>> perf record -a -e power/energy-pkg/ 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?
> RAPL events cannot generate interrupts, so I don't think you can sample
> like this.
>
> You can possibly sample using some other event (like one of the software
> clock events) and include the RAPL event in the list of events to record,
> not sure if that will accomplish what you're trying to do.
>
> Vince

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 ?