[igt-dev] [PATCH i-g-t v6] tests/perf_pmu: Verify engine busyness accuracy

[Chris Wilson]

Quoting Tvrtko Ursulin (2018-02-15 15:34:53)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> A subtest to verify that the engine busyness is reported with expected
> accuracy on platforms where the feature is available.
> 
> We test three patterns: 2%, 50% and 98% load per engine.
> 
> v2:
>  * Use spin batch instead of nop calibration.
>  * Various tweaks.
> 
> v3:
>  * Change loops to be time based.
>  * Use __igt_spin_batch_new inside timing sensitive loops.
>  * Fixed PWM sleep handling.
> 
> v4:
>  * Use restarting spin batch.
>  * Calibrate more carefully by looking at the real PWM loop.
> 
> v5:
>  * Made standalone.
>  * Better info messages.
>  * Tweak sleep compensation.
> 
> v6:
>  * Some final tweaks. (Chris Wilson)
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
> +
> +       /* Sampling platforms cannot reach the high accuracy criteria. */
> +       igt_require(gem_has_execlists(gem_fd));

But we don't handle guc, right?
igt_skip_on(gem_has_guc_submission(gem_fd)) ?

https://intel-gfx-ci.01.org/tree/drm-tip/kasan_2/fi-skl-guc/igt@perf_pmu@busy-accuracy-2-vecs0.html

Or at least it doesn't work to sufficient accuracy. And bsw hung.
-Chris