[igt-dev] [PATCH i-g-t] lib/igt_perf: Find active perf CPU

[Tvrtko Ursulin]

On 21/02/2018 10:34, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2018-02-21 10:29:57)
>> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>>
>> Instead of assuming PMU runs on CPU0, try all possible CPUs if that is not
>> the case. This makes the callers handle fallout from broken tests better,
>> as well as sysadmin interventions where callers are not tests.
>>
>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> 
> As a bonus it also helps document the perf_open() call.
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>

Thanks!

> Are we not allowed to pass cpu=-1 for any/all cpus?

No, that is documented to return -EINVAL from perf core. I guess it 
comes from the per-CPU nature of perf.

Regards,

Tvrtko