Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: > Quoting Mika Kuoppala (2021-01-12 19:19:34) >> Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes: >> >> > 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@xxxxxxxxxxxxxxxxxx> >> > --- >> > drivers/gpu/drm/i915/gt/selftest_engine_pm.c | 4 ++-- >> > 1 file changed, 2 insertions(+), 2 deletions(-) >> > >> > diff --git a/drivers/gpu/drm/i915/gt/selftest_engine_pm.c b/drivers/gpu/drm/i915/gt/selftest_engine_pm.c >> > index ca080445695e..c3d965279fc3 100644 >> > --- a/drivers/gpu/drm/i915/gt/selftest_engine_pm.c >> > +++ b/drivers/gpu/drm/i915/gt/selftest_engine_pm.c >> > @@ -112,11 +112,11 @@ static int __measure_timestamps(struct intel_context *ce, >> > >> > /* Run the request for a 100us, sampling timestamps before/after */ >> > preempt_disable(); >> >> Do you need to promote this to local_irq_disable() ? > > Good suggestion. Will try to remember if we still see discrepancies... > > Interrupt handlers are meant to <5us, right??? With both test types, we might sometimes find out what they are :) Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> > -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
