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

[Chris Wilson]

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.
-Chris