[PATCH v4 00/11] Preemption support for A7XX
Rob Clark
robdclark at gmail.com
Wed Sep 18 15:39:30 UTC 2024
On Wed, Sep 18, 2024 at 12:46 AM Neil Armstrong
<neil.armstrong at linaro.org> wrote:
>
> Hi,
>
> On 17/09/2024 13:14, Antonino Maniscalco wrote:
> > 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@codeaurora.org
> >
> > Signed-off-by: Antonino Maniscalco <antomani103 at gmail.com>
> > ---
> > Changes in v4:
> > - Added missing register in pwrup list
> > - Removed and rearrange barriers
> > - Renamed `skip_inline_wptr` to `restore_wptr`
> > - Track ctx seqno per ring
> > - Removed secure preempt context
> > - NOP out postamble to disable it instantly
> > - Only emit pwrup reglist once
> > - Document bv_rptr_addr
> > - Removed unused A6XX_PREEMPT_USER_RECORD_SIZE
> > - Set name on preempt record buffer
> > - Link to v3: https://lore.kernel.org/r/20240905-preemption-a750-t-v3-0-fd947699f7bc@gmail.com
> >
> > 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@gmail.com
> >
> > 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@gmail.com
> >
> > ---
> > Antonino Maniscalco (11):
> > drm/msm: Fix bv_fence being used as bv_rptr
> > drm/msm/A6XX: Track current_ctx_seqno per ring
> > 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/a2xx_gpu.c | 2 +-
> > drivers/gpu/drm/msm/adreno/a3xx_gpu.c | 2 +-
> > drivers/gpu/drm/msm/adreno/a4xx_gpu.c | 2 +-
> > drivers/gpu/drm/msm/adreno/a5xx_gpu.c | 6 +-
> > drivers/gpu/drm/msm/adreno/a6xx_catalog.c | 7 +-
> > drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 325 ++++++++++++++-
> > drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 174 ++++++++
> > drivers/gpu/drm/msm/adreno/a6xx_preempt.c | 440 +++++++++++++++++++++
> > drivers/gpu/drm/msm/adreno/adreno_gpu.h | 9 +-
> > drivers/gpu/drm/msm/msm_drv.c | 4 +
> > drivers/gpu/drm/msm/msm_gpu.c | 2 +-
> > drivers/gpu/drm/msm/msm_gpu.h | 11 -
> > drivers/gpu/drm/msm/msm_gpu_trace.h | 28 ++
> > drivers/gpu/drm/msm/msm_ringbuffer.h | 18 +
> > 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 +-
> > 20 files changed, 1117 insertions(+), 66 deletions(-)
> > ---
> > base-commit: 7c626ce4bae1ac14f60076d00eafe71af30450ba
> > change-id: 20240815-preemption-a750-t-fcee9a844b39
> >
> > Best regards,
>
> I've been running vulkan-cts (1.3.7.3-0-gd71a36db16d98313c431829432a136dbda692a08 from Yocto)
> on SM8650-QRD, SM8550-QRD & SM8450-HDK boards with enable_preemption in default value
> and forced to 1, and I've seen no regression so far
>
> On SM8550, I've seen a few:
> platform 3d6a000.gmu: [drm:a6xx_hfi_send_msg.constprop.0 [msm]] *ERROR* Message HFI_H2F_MSG_GX_BW_PERF_VOTE id 2743 timed out waiting for response
> platform 3d6a000.gmu: [drm:a6xx_hfi_send_msg.constprop.0 [msm]] *ERROR* Unexpected message id 2743 on the response queue
> but it's unrelated to preempt
>
> and on SM8450:
> platform 3d6a000.gmu: [drm:a6xx_gmu_set_oob [msm]] *ERROR* Timeout waiting for GMU OOB set GPU_SET: 0x0
> msm_dpu ae01000.display-controller: [drm:hangcheck_handler [msm]] *ERROR* 7.3.0.1: hangcheck detected gpu lockup rb 0!
> msm_dpu ae01000.display-controller: [drm:hangcheck_handler [msm]] *ERROR* 7.3.0.1: completed fence: 331235
> msm_dpu ae01000.display-controller: [drm:hangcheck_handler [msm]] *ERROR* 7.3.0.1: submitted fence: 331236
> adreno 3d00000.gpu: [drm:a6xx_irq [msm]] *ERROR* gpu fault ring 0 fence 50de4 status 00800005 rb 0000/0699 ib1 0000000000000000/0000 ib2 0000000000000000/0000
> msm_dpu ae01000.display-controller: [drm:recover_worker [msm]] *ERROR* 7.3.0.1: hangcheck recover!
> msm_dpu ae01000.display-controller: [drm:recover_worker [msm]] *ERROR* 7.3.0.1: offending task: deqp-vk (/usr/lib/vulkan-cts/deqp-vk)
> msm_dpu ae01000.display-controller: [drm:recover_worker [msm]] *ERROR* 7.3.0.1: hangcheck recover!
> leading to a VK_ERROR_DEVICE_LOST, but again unrelated to preempt support.
I suspect on newer devices we have trouble resetting the GMU, leading
to (what I assume is happening here) the CPU thinking the GMU is in a
different state than it is.
Which has led to some stability issues on a660 in mesa CI, if anything
crashes the gpu in the CI run it tends to kill the rest of the run
until the board is power cycled.
https://gitlab.freedesktop.org/drm/msm/-/issues/37
I think we have some work to do on making recovery more robust on
things newer than early a6xx things.
BR,
-R
> So you can also add:
> Tested-by: Neil Armstrong <neil.armstrong at linaro.org> # on SM8550-QRD
> Tested-by: Neil Armstrong <neil.armstrong at linaro.org> # on SM8450-HDK
>
> Thanks,
> Neil
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