[igt-dev] [Intel-gfx] [PATCH i-g-t] i915/perf_pmu: Exercise I915_PMU_SOFTWARE_GT_AWAKE_TIME

[Tvrtko Ursulin]

On 17/12/2020 17:39, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2020-12-17 17:33:05)
>>
>> On 17/12/2020 17:26, Chris Wilson wrote:
>>> Measure the sample gt-awake time while each engine and every engine is
>>> busy. They should all report the same duration, the elapsed runtime of
>>> the batch.
>>>
>>> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>>> Cc: Tvrtko Ursulin <tvrtko.ursulin at linux.intel.com>
>>> ---
>>>    include/drm-uapi/i915_drm.h |  3 ++-
>>>    tests/i915/perf_pmu.c       | 42 +++++++++++++++++++++++++++++++++++++
>>>    2 files changed, 44 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/include/drm-uapi/i915_drm.h b/include/drm-uapi/i915_drm.h
>>> index ef696d1a5..bf9ea471c 100644
>>> --- a/include/drm-uapi/i915_drm.h
>>> +++ b/include/drm-uapi/i915_drm.h
>>> @@ -177,8 +177,9 @@ enum drm_i915_pmu_engine_sample {
>>>    #define I915_PMU_REQUESTED_FREQUENCY        __I915_PMU_OTHER(1)
>>>    #define I915_PMU_INTERRUPTS         __I915_PMU_OTHER(2)
>>>    #define I915_PMU_RC6_RESIDENCY              __I915_PMU_OTHER(3)
>>> +#define I915_PMU_SOFTWARE_GT_AWAKE_TIME      __I915_PMU_OTHER(4)
>>>    
>>> -#define I915_PMU_LAST I915_PMU_RC6_RESIDENCY
>>> +#define I915_PMU_LAST /* Deprecated - do not use */ I915_PMU_RC6_RESIDENCY
>>>    
>>>    /* Each region is a minimum of 16k, and there are at most 255 of them.
>>>     */
>>> diff --git a/tests/i915/perf_pmu.c b/tests/i915/perf_pmu.c
>>> index c2b186d39..90182074b 100644
>>> --- a/tests/i915/perf_pmu.c
>>> +++ b/tests/i915/perf_pmu.c
>>> @@ -883,6 +883,42 @@ sema_busy(int gem_fd,
>>>        close(fd[1]);
>>>    }
>>>    
>>> +static void test_awake(int i915)
>>> +{
>>> +     const struct intel_execution_engine2 *e;
>>> +     unsigned long slept;
>>> +     uint64_t val;
>>> +     int fd;
>>> +
>>> +     fd = perf_i915_open(i915, I915_PMU_SOFTWARE_GT_AWAKE_TIME);
>>> +     igt_skip_on(fd < 0);
>>> +
>>> +     /* Check that each engine is captured by the GT wakeref */
>>> +     __for_each_physical_engine(i915, e) {
>>> +             igt_spin_new(i915, .engine = e->flags);
>>> +
>>> +             val = pmu_read_single(fd);
>>> +             slept = measured_usleep(batch_duration_ns / 1000);
>>> +             val = pmu_read_single(fd) - val;
>>> +
>>> +             gem_quiescent_gpu(i915);
>>> +             assert_within_epsilon(val, slept, tolerance);
>>> +     }
>>> +
>>> +     /* And that the total GT wakeref matches walltime not summation */
>>> +     __for_each_physical_engine(i915, e)
>>> +             igt_spin_new(i915, .engine = e->flags);
>>> +
>>> +     val = pmu_read_single(fd);
>>> +     slept = measured_usleep(batch_duration_ns / 1000);
>>> +     val = pmu_read_single(fd) - val;
>>> +
>>> +     gem_quiescent_gpu(i915);
>>> +     assert_within_epsilon(val, slept, tolerance);
>>> +
>>
>> Erm who terminates all those spinners? :)
> 
> gem_quiescent_gpu() calls igt_terminate_spins(). Hmm, I actually thought
> it freed them too, but what's a small leak...

Okay, I'm fine with that.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Regards,

Tvrtko