[Intel-gfx] [PATCH i-g-t 06/11] tests/perf: make enable-disable more reliable

[Chris Wilson]

Quoting Lionel Landwerlin (2017-08-04 12:20:35)
> Estimation of the amount of reports can only refer to periodic ones,
> as context switch reports completely depend on what happens on the
> system. Also generate some load to prevent clock frequency changes to
> impact our measurement.

If clock frequency is a fundamental invariant required for the test,
set the clock frequency via sysfs:
	/sys/class/drm/card0/gt_(min|max|boost)_freq_mhz
-Chris