[Intel-gfx] [PATCH i-g-t 2/3] tests/perf_pmu: Simplify interrupt testing

[Chris Wilson]

Quoting Tvrtko Ursulin (2017-12-19 15:45:42)
> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> 
> Rather than calibrate and emit nop batches, use a manually signalled chain
> of spinners to generate the desired interrupts.
> 
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> ---
>         } while (idle != busy);
>  
> -       /* Install the fences and enable signaling */
> -       igt_assert_eq(poll(&pfd, 1, 10), 0);
> +       /* Process the batch queue. */
> +       pfd.events = POLLIN;
> +       for (int i = 0; i < target; i++) {
> +               const unsigned int timeout_ms = test_duration_ms / target;

I think you want
	timeout_ms = (i + 1) * test_duration_ms / target;
? Otherwise all the batches have the same relative-to-now timeout (not
relative to the start of the batch).
-Chris