On Wed, May 26, 2021 at 04:33:56PM -0700, 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 > > 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> You have a one-line hunk in the next patch that probably should be here. With that moved. Reviewed-by: Daniel Vetter <daniel.vetter@xxxxxxxx> Also did you get an ack from Carl on these? -Daniel > --- > 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 > -- > 2.28.0 > > _______________________________________________ > 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
