On Tue, 30 Nov 2021 05:20:05 -0800, Anshuman Gupta wrote: > > gt_pm selftest calculates engine ticks cycles and wall time > cycles by delta of respective engine elapsed TIMESTAMP and ktime > for period of 1000us. > It compares the engine ticks cycles with wall time cycles. > > Disable local cpu interrupt so that interrupt handler does not > switch out the thread during measure_clocks() and prevent > miscalculation of engine tick cycles. Reviewed-by: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx> > v2: > - nuke preempt_{disable,enable}, as disable_local_irq() > disable the preemption. (Chris) > > Cc: Chris P Wilson <chris.p.wilson@xxxxxxxxx> > Cc: Badal Nilawar <badal.nilawar@xxxxxxxxx> > Cc: Ashutosh Dixit <ashutosh.dixit@xxxxxxxxx> > Signed-off-by: Anshuman Gupta <anshuman.gupta@xxxxxxxxx> > --- > drivers/gpu/drm/i915/gt/selftest_gt_pm.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c > index b9441217ca3d..55c5cdb99f45 100644 > --- a/drivers/gpu/drm/i915/gt/selftest_gt_pm.c > +++ b/drivers/gpu/drm/i915/gt/selftest_gt_pm.c > @@ -43,7 +43,7 @@ static void measure_clocks(struct intel_engine_cs *engine, > int i; > > for (i = 0; i < 5; i++) { > - preempt_disable(); > + local_irq_disable(); > cycles[i] = -ENGINE_READ_FW(engine, RING_TIMESTAMP); > dt[i] = ktime_get(); > > @@ -51,7 +51,7 @@ static void measure_clocks(struct intel_engine_cs *engine, > > dt[i] = ktime_sub(ktime_get(), dt[i]); > cycles[i] += ENGINE_READ_FW(engine, RING_TIMESTAMP); > - preempt_enable(); > + local_irq_enable(); > } > > /* Use the median of both cycle/dt; close enough */ > -- > 2.26.2 >