drm/i915/selftests: Rearrange ktime_get to reduce latency against CS

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In our tests where we measure the elapsed time on both the CPU and CS
using a udelay, our CS results match the udelay much more accurately
than the ktime (even when using ktime_get_fast_ns). With preemption
disabled, we can go one step lower than ktime and use local_clock.

Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/2919
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Andi Shyti <andi.shyti@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210108204026.20682-3-chris@chris-wilson.co.uk

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Chris Wilson 2021-01-08 20:40:22 +00:00

parent c318a203ea

commit 0399d0e33a

1 changed files with 2 additions and 2 deletions

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drivers/gpu/drm/i915/gt/selftest_engine_pm.c

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