[Intel-gfx] [PATCH 1/2] drm/i915/trace: Describe engines as class:instance pairs

[Chris Wilson]

Quoting Tvrtko Ursulin (2018-05-25 08:11:41)
> 
> On 24/05/2018 17:13, Lionel Landwerlin wrote:
> > On 24/05/18 17:07, Tvrtko Ursulin wrote:
> >>
> >> On 24/05/2018 16:53, Lionel Landwerlin wrote:
> >>> On 24/05/18 16:04, Tvrtko Ursulin wrote:
> >>>> From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >>>>
> >>>> Instead of using the engine->id, use uabi_class:instance pairs in 
> >>>> trace-
> >>>> points including engine info.
> >>>>
> >>>> This will be more readable, more future proof and more stable for
> >>>> userspace consumption.
> >>>>
> >>>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >>>> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> >>>> Cc: svetlana.kukanova at intel.com
> >>> Don't you want engine->uabi_id instead of engine->instance ?
> >>
> >> No, class:instance is the new engine identifier - why do you think we 
> >> would need legacy engine->uabi_id?
> > 
> > Maybe I forgot about your engine listing series...
> > I would expect the tracepoint to match the engines listed through that 
> > uapi.
> 
> Yeah I don't have engine->uabi_id exported in engine discovery. I could 
> add it, but given how we don't plan to extend it (the legacy engine 
> selection), I think it is not needed. If there will be popular demand 
> though can do it.

Also that we plan to conflate the I915_EXEC_RING selector so that
engine->uabi_id would no longer be a unique mapping, will add to the
confusion.
-Chris