[Intel-gfx] [PATCH] drm/i915: sync I915_PMU_MAX_GTS to I915_MAX_GT

[Dixit, Ashutosh]

On Thu, 01 Jun 2023 11:22:18 -0700, Dixit, Ashutosh wrote:
>
> On Wed, 31 May 2023 14:35:47 -0700, Matt Atwood wrote:
> >
>
> Hi Matt,
>
> > Set I915_PMU_MAX_GTS to value in I915_MAX_GT, theres no reason for these
> > values to be different.

Also, we can't be so sure so as to be able to say "theres no reason for
these values to be different" till we have actually verified it. E.g. there
are various bitfields in the code which might not fit in a u32 if we
increase MAX_GT from 2 to 4. Has this been verified?

If anything, to keep the code from doing unnecessary stuff, IMO I915_MAX_GT
should be reduced to 2 and should be increased to 4 only once/if we have
i915 supported platforms with 4 GT's.

Thanks.
--
Ashutosh


> >
> > Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> > Cc: Umesh Nerlige Ramappa <umesh.nerlige.ramappa at intel.com>
> > Cc: Ashutosh Dixit <ashutosh.dixit at intel.com>
>
> I don't believe the mailer actually Cc'd us. I just saw this and am Cc'ing
> the people who authored/reviewed the previous series now.
>
> > Signed-off-by: Matt Atwood <matthew.s.atwood at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_pmu.h | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_pmu.h b/drivers/gpu/drm/i915/i915_pmu.h
> > index 33d80fbaab8b..aa929d8c224a 100644
> > --- a/drivers/gpu/drm/i915/i915_pmu.h
> > +++ b/drivers/gpu/drm/i915/i915_pmu.h
> > @@ -38,7 +38,7 @@ enum {
> >	__I915_NUM_PMU_SAMPLERS
> >  };
> >
> > -#define I915_PMU_MAX_GTS 2
> > +#define I915_PMU_MAX_GTS 4
>
> This was a discussed during the previous review and it was decided to keep
> the two values (I915_PMU_MAX_GTS and I915_MAX_GT) different. There are
> currently no platforms and there will be no i915 supported platforms with
> MAX_GT 4. So I prefer to leave the values as they currently are. Unless
> Umesh or Tvrtko agrees to this patch.
>
> Thanks.
> --
> Ashutosh
>
> >
> >  /*
> >   * How many different events we track in the global PMU mask.
> > --
> > 2.40.0
> >