lkml.org 
[lkml]   [2017]   [May]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] perf/x86/intel: Drop kernel samples even though :u is specified
From
Date


On 5/19/2017 8:10 PM, Peter Zijlstra wrote:
> On Fri, May 19, 2017 at 08:06:09PM +0800, Jin, Yao wrote:
>> SNIP
>>
>>> I would much rather see this in generic code, somewhere around
>>> __perf_event_overflow() I suppose. That would retain proper accounting
>>> for the interrupt rate etc..
>>>
>>> Also it would work for all architectures. Because I'm thinking more than
>>> just x86 will suffer from skid.
>> Yes, moving to generic code is better. Thanks for the suggestion! I will do
>> that.
>>
>>> If you're really worried, I suppose you can put it behind a PERF_PMU_CAP
>>> flag or something.
>> I guess what you are suggesting is to add checking like:
>>
>> if (is_sampling_event(event)) {
>> if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
>> return;
>> }
>> }
> Ah, I was more thinking of something like PERF_PMU_CAP_NO_SKID or
> something that would skip the test and preserve current behaviour.

OK, I understand now. For example, for PEBS event, its capabilities
should be set with PERF_PMU_CAP_NO_SKID.

If the event's capabilities is set with PERF_PMU_CAP_NO_SKID, it should
skip the checking and keep current behavior.

Thanks
Jin Yao

\
 
 \ /
  Last update: 2017-05-19 14:25    [W:0.060 / U:5.308 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site