> -----Original Message-----
> From: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> Sent: Monday, January 11, 2021 1:03 PM
> To: Abodunrin, Akeem G <akeem.g.abodunrin@xxxxxxxxx>; intel-
> gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: stable@ <vger.kernel.org stable@xxxxxxxxxxxxxxx>; Randy Wright
> <rwright@xxxxxxx>
> Subject: Re: [PATCH 1/3] drm/i915/gt: Limit VFE threads based on
> GT
>
> Quoting Abodunrin, Akeem G (2021-01-11 20:25:34)
> > > static void
> > > batch_get_defaults(struct drm_i915_private *i915, struct batch_vals *bv)
> {
> > > if (IS_HASWELL(i915)) {
> > > - bv->max_primitives = 280;
> > > - bv->max_urb_entries = MAX_URB_ENTRIES;
> > > + switch (INTEL_INFO(i915)->gt) {
> > > + default:
> > > + case 1:
> > > + bv->max_threads = 70;
> > > + break;
> > > + case 2:
> > > + bv->max_threads = 140;
> > > + break;
> > > + case 3:
> > > + bv->max_threads = 280;
> > > + break;
> > > + }
> > > bv->surface_height = 16 * 16;
> > > bv->surface_width = 32 * 2 * 16;
> > > } else {
> > > - bv->max_primitives = 128;
> > > - bv->max_urb_entries = MAX_URB_ENTRIES / 2;
> > > + switch (INTEL_INFO(i915)->gt) {
> > > + default:
> > > + case 1: /* including vlv */
> > > + bv->max_threads = 36;
> > > + break;
> > > + case 2:
> > > + bv->max_threads = 128;
> > > + break;
> > > + }
> > Do we really need to hardcode max number of threads per gt/platform?
> Why not calculating the number of active threads from the no_of_slices *
> 1024? - Also, is "64" not the minimum number of threads supported?
>
> ivb,byt,hsw each has different numbers of threads per subslice, and each gt
> has a different number of subslice/slice (and not a simple doubling of
> subslice/slice from 1 -> 2 -> 3, although the total is!).
>
> It's a choice between encoding a tuple for (num_threads, num_subslices,
> num_slices) or the combined value.
>
> The goal is to run a shader in each HW thread to clear the thread-local
> registers, and only one shader in each.
> -Chris
Okay, let's go with simplified solution to achieve our goal here, instead of complex calculation...
Reviewed-by: Akeem G Abodunrin <akeem.g.abodunrin@xxxxxxxxx>
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