This series implements preemption for A7XX targets, which allows the GPU to switch to an higher priority ring when work is pushed to it, reducing latency for high priority submissions. This series enables L1 preemption with skip_save_restore which requires the following userspace patches to function: https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/30544 A flag is added to `msm_submitqueue_create` to only allow submissions from compatible userspace to be preempted, therefore maintaining compatibility. Preemption is currently only enabled by default on A750, it can be enabled on other targets through the `enable_preemption` module parameter. This is because more testing is required on other targets. For testing on other HW it is sufficient to set that parameter to a value of 1, then using the branch of mesa linked above, `TU_DEBUG=hiprio` allows to run any application as high priority therefore preempting submissions from other applications. The `msm_gpu_preemption_trigger` and `msm_gpu_preemption_irq` traces added in this series can be used to observe preemption's behavior as well as measuring preemption latency. Some commits from this series are based on a previous series to enable preemption on A6XX targets: https://lkml.kernel.org/1520489185-21828-1-git-send-email-smasetty@xxxxxxxxxxxxxx Signed-off-by: Antonino Maniscalco <antomani103@xxxxxxxxx> --- Changes in v3: - Added documentation about preemption - Use quirks to determine which target supports preemption - Add a module parameter to force disabling or enabling preemption - Clear postamble when profiling - Define A6XX_CP_CONTEXT_SWITCH_CNTL_LEVEL fields in a6xx.xml - Make preemption records MAP_PRIV - Removed user ctx record (NON_PRIV) and patch 2/9 as it's not needed anymore - Link to v2: https://lore.kernel.org/r/20240830-preemption-a750-t-v2-0-86aeead2cd80@xxxxxxxxx Changes in v2: - Added preept_record_size for X185 in PATCH 3/7 - Added patches to reset perf counters - Dropped unused defines - Dropped unused variable (fixes warning) - Only enable preemption on a750 - Reject MSM_SUBMITQUEUE_ALLOW_PREEMPT for unsupported targets - Added Akhil's Reviewed-By tags to patches 1/9,2/9,3/9 - Added Neil's Tested-By tags - Added explanation for UAPI changes in commit message - Link to v1: https://lore.kernel.org/r/20240815-preemption-a750-t-v1-0-7bda26c34037@xxxxxxxxx --- Antonino Maniscalco (10): drm/msm: Fix bv_fence being used as bv_rptr drm/msm: Add a `preempt_record_size` field drm/msm: Add CONTEXT_SWITCH_CNTL bitfields drm/msm/A6xx: Implement preemption for A7XX targets drm/msm/A6xx: Sync relevant adreno_pm4.xml changes drm/msm/A6xx: Use posamble to reset counters on preemption drm/msm/A6xx: Add traces for preemption drm/msm/A6XX: Add a flag to allow preemption to submitqueue_create drm/msm/A6xx: Enable preemption for A750 Documentation: document adreno preemption Documentation/gpu/msm-preemption.rst | 98 +++++ drivers/gpu/drm/msm/Makefile | 1 + drivers/gpu/drm/msm/adreno/a6xx_catalog.c | 7 +- drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 331 +++++++++++++++- drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 166 ++++++++ drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 430 +++++++++++++++++++++ drivers/gpu/drm/msm/adreno/adreno_gpu.h | 9 +- drivers/gpu/drm/msm/msm_drv.c | 4 + drivers/gpu/drm/msm/msm_gpu_trace.h | 28 ++ drivers/gpu/drm/msm/msm_ringbuffer.h | 8 + drivers/gpu/drm/msm/msm_submitqueue.c | 3 + drivers/gpu/drm/msm/registers/adreno/a6xx.xml | 7 +- .../gpu/drm/msm/registers/adreno/adreno_pm4.xml | 39 +- include/uapi/drm/msm_drm.h | 5 +- 14 files changed, 1094 insertions(+), 42 deletions(-) --- base-commit: 7c626ce4bae1ac14f60076d00eafe71af30450ba change-id: 20240815-preemption-a750-t-fcee9a844b39 Best regards, -- Antonino Maniscalco <antomani103@xxxxxxxxx>
