From: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxx> <tldr> Replacing FIFO with a flavour of deadline driven scheduling and removing round- robin. Connecting the scheduler with dma-fence deadlines. First draft and testing by different drivers and feedback would be nice. I was only able to test it with amdgpu. Other drivers may not even compile. </tldr> If I remember correctly Christian mentioned recently (give or take) that maybe round-robin could be removed. That got me thinking how and what could be improved and simplified. So I played a bit in the scheduler code and came up with something which appears to not crash at least. Whether or not there are significant advantages apart from maybe code consolidation and reduction is the main thing to be determined. One big question is whether round-robin can really be removed. Does anyone use it, rely on it, or what are even use cases where it is much better than FIFO. See "drm/sched: Add deadline policy" commit message for a short description on what flavour of deadline scheduling it is. But in essence it should a more fair FIFO where higher priority can not forever starve lower priorities. "drm/sched: Connect with dma-fence deadlines" wires up dma-fence deadlines to the scheduler because it is easy and makes logical sense with this. And I noticed userspace already uses it so why not wire it up fully. Otherwise the series is a bit of progression from consolidating RR into FIFO code paths and going from there to deadline and then to a change in how dependencies are handled. And code simplification to 1:1 run queue to scheduler relationship, because deadline does not need per priority run queues. There is quite a bit of code to go throught here so I think it could be even better if other drivers could give it a spin as is and see if some improvements can be detected. Or at least no regressions. Cc: Christian König <christian.koenig@xxxxxxx> Cc: Danilo Krummrich <dakr@xxxxxxxxxx> Cc: Matthew Brost <matthew.brost@xxxxxxxxx> Cc: Philipp Stanner <pstanner@xxxxxxxxxx> Tvrtko Ursulin (14): drm/sched: Delete unused update_job_credits drm/sched: Remove idle entity from tree drm/sched: Implement RR via FIFO drm/sched: Consolidate entity run queue management drm/sched: Move run queue related code into a separate file drm/sched: Ignore own fence earlier drm/sched: Resolve same scheduler dependencies earlier drm/sched: Add deadline policy drm/sched: Remove FIFO and RR and simplify to a single run queue drm/sched: Queue all free credits in one worker invocation drm/sched: Connect with dma-fence deadlines drm/sched: Embed run queue singleton into the scheduler dma-fence: Add helper for custom fence context when merging fences drm/sched: Resolve all job dependencies in one go drivers/dma-buf/dma-fence-unwrap.c | 8 +- drivers/gpu/drm/amd/amdgpu/amdgpu_cs.c | 6 +- drivers/gpu/drm/amd/amdgpu/amdgpu_job.c | 27 +- drivers/gpu/drm/amd/amdgpu/amdgpu_job.h | 5 +- drivers/gpu/drm/amd/amdgpu/amdgpu_trace.h | 8 +- drivers/gpu/drm/amd/amdgpu/amdgpu_vm_sdma.c | 8 +- drivers/gpu/drm/amd/amdgpu/amdgpu_xcp.c | 8 +- drivers/gpu/drm/scheduler/Makefile | 2 +- drivers/gpu/drm/scheduler/sched_entity.c | 316 ++++++----- drivers/gpu/drm/scheduler/sched_fence.c | 5 +- drivers/gpu/drm/scheduler/sched_main.c | 587 +++++--------------- drivers/gpu/drm/scheduler/sched_rq.c | 199 +++++++ include/drm/gpu_scheduler.h | 74 ++- include/linux/dma-fence-unwrap.h | 31 +- 14 files changed, 606 insertions(+), 678 deletions(-) create mode 100644 drivers/gpu/drm/scheduler/sched_rq.c -- 2.47.1
