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??? -Chris _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
