[PATCH 17/26] drm/amd/display: implement PERF_TRACE on Linux

[Christian König]

Am 12.10.2018 um 18:56 schrieb Michel Dänzer:
> On 2018-10-11 12:09 a.m., Bhawanpreet Lakha wrote:
>> From: David Francis <David.Francis at amd.com>
>>
>> [Why]
>> A quick-and-dirty way of getting performance data for the amdgpu
>> driver would make performance improvements easier
>>
>> [How]
>> The PERF_TRACE functionality is a tic-toc style debug method.
>> Put PERF_TRACE calls on either side of the code you want to test.
>> PERF_TRACE requires access to struct dc_context.  PERF_TRACE()
>> will pick up the CTX macro, and PERF_TRACE_CTX(struct dc_context)
>> allows you to pass the context explicitly.
>>
>> The last 20 results can be read through the debugfs entry
>> amdgpu_perf_trace.  Each result contains the time in ns and
>> number of GPU read/writes since the result before it.
>>
>> In my experimentation, each PERF_TRACE() call uses at most 700ns
> Should this use the Linux tracing infrastructure?

Yeah, agree that looks like reimplementing the tracing infrastructure to 
me as well.

Christian.