[igt-dev] [PATCH i-g-t] i915/perf_pmu: Measure how many batches can fit into the ring

[Summers, Stuart]

On Wed, 2019-12-04 at 19:21 +0000, Chris Wilson wrote:
> Quoting Summers, Stuart (2019-12-04 19:13:16)
> > On Wed, 2019-12-04 at 13:20 +0000, Chris Wilson wrote:
> > > Do not blindly assume 30 spin batches will always fit into the
> > > ring,
> > > but
> > > use our measurement tool instead.
> > > 
> > > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > > Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > > ---
> > >  tests/perf_pmu.c | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > > 
> > > diff --git a/tests/perf_pmu.c b/tests/perf_pmu.c
> > > index de4c231dd..8e50ac9a0 100644
> > > --- a/tests/perf_pmu.c
> > > +++ b/tests/perf_pmu.c
> > > @@ -42,6 +42,7 @@
> > >  #include "igt_perf.h"
> > >  #include "igt_sysfs.h"
> > >  #include "igt_pm.h"
> > > +#include "i915/gem_ring.h"
> > >  #include "sw_sync.h"
> > >  
> > >  IGT_TEST_DESCRIPTION("Test the i915 pmu perf interface");
> > > @@ -1276,8 +1277,9 @@ static void cpu_hotplug(int gem_fd)
> > >  static void
> > >  test_interrupts(int gem_fd)
> > >  {
> > > +     const int target =
> > > +             gem_measure_ring_inflight(gem_fd,
> > > I915_EXEC_DEFAULT,
> > > 0);
> > 
> > In case we ever want to change this engine, should we make
> > I915_EXEC_DEFAULT a macro within this test?
> 
> Not really, EXEC_DEFAULT itself is the placeholder for first engine
> on
> the system... I really should land my ffs() before it makes a
> difference.
> > 
> > Looks a lot better. My only question here is can we make
> > gem_measure_ring_inflight a generic routine instead of something
> > i915-
> > specific, since we're using this in one of the cross-arch tests?
> 
> This is not a generic test. Simply has not been moved yet.

Makes sense then.

Reviewed-by: Stuart Summers <stuart.summers at intel.com>

> -Chris
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