On Thu, May 27, 2021 at 11:06:38AM +0100, Tvrtko Ursulin wrote: > > On 27/05/2021 00:33, Matthew Brost wrote: > > Add entry for i915 GuC submission / DRM scheduler integration plan. > > Follow up patch with details of new parallel submission uAPI to come. > > > > v2: > > (Daniel Vetter) > > - Expand explaination of why bonding isn't supported for GuC > > submission > > - CC some of the DRM scheduler maintainers > > - Add priority inheritance / boosting use case > > - Add reasoning for removing in order assumptions > > (Daniel Stone) > > - Add links to priority spec > > Where will the outstanding items like, from the top of my head only, error > capture and open source logging tool be tracked? I thought here but maybe > not. I thought the same that we'd put these really important bits into the rfc/todo here. Matt, can you pls do that? -Daniel > > Regards, > > Tvrtko > > > Cc: Christian König <christian.koenig@xxxxxxx> > > Cc: Luben Tuikov <luben.tuikov@xxxxxxx> > > Cc: Alex Deucher <alexander.deucher@xxxxxxx> > > Cc: Steven Price <steven.price@xxxxxxx> > > Cc: Jon Bloomfield <jon.bloomfield@xxxxxxxxx> > > Cc: Jason Ekstrand <jason@xxxxxxxxxxxxxx> > > Cc: Dave Airlie <airlied@xxxxxxxxx> > > Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx> > > Cc: Jason Ekstrand <jason@xxxxxxxxxxxxxx> > > Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx > > Signed-off-by: Matthew Brost <matthew.brost@xxxxxxxxx> > > --- > > Documentation/gpu/rfc/i915_scheduler.rst | 85 ++++++++++++++++++++++++ > > Documentation/gpu/rfc/index.rst | 4 ++ > > 2 files changed, 89 insertions(+) > > create mode 100644 Documentation/gpu/rfc/i915_scheduler.rst > > > > diff --git a/Documentation/gpu/rfc/i915_scheduler.rst b/Documentation/gpu/rfc/i915_scheduler.rst > > new file mode 100644 > > index 000000000000..7faa46cde088 > > --- /dev/null > > +++ b/Documentation/gpu/rfc/i915_scheduler.rst > > @@ -0,0 +1,85 @@ > > +========================================= > > +I915 GuC Submission/DRM Scheduler Section > > +========================================= > > + > > +Upstream plan > > +============= > > +For upstream the overall plan for landing GuC submission and integrating the > > +i915 with the DRM scheduler is: > > + > > +* Merge basic GuC submission > > + * Basic submission support for all gen11+ platforms > > + * Not enabled by default on any current platforms but can be enabled via > > + modparam enable_guc > > + * Lots of rework will need to be done to integrate with DRM scheduler so > > + no need to nit pick everything in the code, it just should be > > + functional, no major coding style / layering errors, and not regress > > + execlists > > + * Update IGTs / selftests as needed to work with GuC submission > > + * Enable CI on supported platforms for a baseline > > + * Rework / get CI heathly for GuC submission in place as needed > > +* Merge new parallel submission uAPI > > + * Bonding uAPI completely incompatible with GuC submission, plus it has > > + severe design issues in general, which is why we want to retire it no > > + matter what > > + * New uAPI adds I915_CONTEXT_ENGINES_EXT_PARALLEL context setup step > > + which configures a slot with N contexts > > + * After I915_CONTEXT_ENGINES_EXT_PARALLEL a user can submit N batches to > > + a slot in a single execbuf IOCTL and the batches run on the GPU in > > + paralllel > > + * Initially only for GuC submission but execlists can be supported if > > + needed > > +* Convert the i915 to use the DRM scheduler > > + * GuC submission backend fully integrated with DRM scheduler > > + * All request queues removed from backend (e.g. all backpressure > > + handled in DRM scheduler) > > + * Resets / cancels hook in DRM scheduler > > + * Watchdog hooks into DRM scheduler > > + * Lots of complexity of the GuC backend can be pulled out once > > + integrated with DRM scheduler (e.g. state machine gets > > + simplier, locking gets simplier, etc...) > > + * Execlist backend will do the minimum required to hook in the DRM > > + scheduler so it can live next to the fully integrated GuC backend > > + * Legacy interface > > + * Features like timeslicing / preemption / virtual engines would > > + be difficult to integrate with the DRM scheduler and these > > + features are not required for GuC submission as the GuC does > > + these things for us > > + * ROI low on fully integrating into DRM scheduler > > + * Fully integrating would add lots of complexity to DRM > > + scheduler > > + * Port i915 priority inheritance / boosting feature in DRM scheduler > > + * Used for i915 page flip, may be useful to other DRM drivers as > > + well > > + * Will be an optional feature in the DRM scheduler > > + * Remove in-order completion assumptions from DRM scheduler > > + * Even when using the DRM scheduler the backends will handle > > + preemption, timeslicing, etc... so it is possible for jobs to > > + finish out of order > > + * Pull out i915 priority levels and use DRM priority levels > > + * Optimize DRM scheduler as needed > > + > > +New uAPI for basic GuC submission > > +================================= > > +No major changes are required to the uAPI for basic GuC submission. The only > > +change is a new scheduler attribute: I915_SCHEDULER_CAP_STATIC_PRIORITY_MAP. > > +This attribute indicates the 2k i915 user priority levels are statically mapped > > +into 3 levels as follows: > > + > > +* -1k to -1 Low priority > > +* 0 Medium priority > > +* 1 to 1k High priority > > + > > +This is needed because the GuC only has 4 priority bands. The highest priority > > +band is reserved with the kernel. This aligns with the DRM scheduler priority > > +levels too. > > + > > +Spec references: > > +---------------- > > +https://www.khronos.org/registry/EGL/extensions/IMG/EGL_IMG_context_priority.txt > > +https://www.khronos.org/registry/vulkan/specs/1.2-extensions/html/chap5.html#devsandqueues-priority > > +https://spec.oneapi.com/level-zero/latest/core/api.html#ze-command-queue-priority-t > > + > > +New parallel submission uAPI > > +============================ > > +Details to come in a following patch. > > diff --git a/Documentation/gpu/rfc/index.rst b/Documentation/gpu/rfc/index.rst > > index 05670442ca1b..91e93a705230 100644 > > --- a/Documentation/gpu/rfc/index.rst > > +++ b/Documentation/gpu/rfc/index.rst > > @@ -19,3 +19,7 @@ host such documentation: > > .. toctree:: > > i915_gem_lmem.rst > > + > > +.. toctree:: > > + > > + i915_scheduler.rst > > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
