[Intel-gfx] [PATCH v2 3/3] drm/i915/perf: enable filtering on multiple contexts

[Chris Wilson]

Quoting Lionel Landwerlin (2020-04-06 14:54:38)
> On 31/03/2020 21:08, Chris Wilson wrote:
> > Quoting Lionel Landwerlin (2020-03-31 12:48:21)
> >> Add 2 new properties to the i915-perf open ioctl to specify an array
> >> of GEM context handles as well as the length of the array.
> > Hmm. The other thought is ctx->engine[] where one context may have more
> > than one logical context instance that OA could track. The extension to
> > track multiple pinned contexts should equally work for multiple engines.
> >
> >       I915_DEFINE_CONTEXT_PARAM_ENGINES(engines, 64) = {};
> >       struct drm_i915_gem_context_param p = {
> >               .ctx_id = gem_context_create(i915),
> >               .param = I915_CONTEXT_PARAM_ENGINES,
> >               .value = to_user_pointer(&engines),
> >               .size = sizeof(struct i915_context_param_engines),
> >       };
> >       gem_context_set_param(i915, &p);
> >
> > would do the trick in creating one context with 64 rcs0 that they may
> > want to track. And that also opens the door to virtual engines over top.
> > -Chris
> 
> 
> I rather punt this away for now :)
> 
> I can't see use cases for Iris/Vulkan.

There's immediate use cases for iris, since it uses 2 contexts instead
of 2 logical instances within one GL/GEM context.

The changes you have here trivially accommodate supporting user defined
engines[], it seems a waste not to.
-Chris