[PATCH v4 00/11] Preemption support for A7XX
Rob Clark
robdclark at gmail.com
Wed Sep 25 19:37:26 UTC 2024
On Tue, Sep 24, 2024 at 8:22 AM Akhil P Oommen <quic_akhilpo at quicinc.com> wrote:
>
> On Tue, Sep 24, 2024 at 07:47:12AM -0700, Rob Clark wrote:
> > On Tue, Sep 24, 2024 at 4:54 AM Antonino Maniscalco
> > <antomani103 at gmail.com> wrote:
> > >
> > > On 9/20/24 7:09 PM, Akhil P Oommen wrote:
> > > > On Wed, Sep 18, 2024 at 09:46:33AM +0200, Neil Armstrong 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.
> > > >>
> > > >> 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
> > > >>
> > > >
> > > > Niel,
> > > >
> > > > On my x1e device, all submissions were somehow going into only a single
> > > > ring, even the compositor's. Not sure why. So effectively preemption was
> > > > not really exercised. I had to force one of the two benchmark I ran
> > > > using the "highprio" mesa debug flag force submittions to ring 0.
> > >
> > > I think that is because GL applications (so most compositors) run
> > > through zink which does not forward GL preemption to vulkan so yeah, for
> > > GL applications the only way of getting preemption is the debug flag.
> >
> > I guess if it is mesa 24.2.x or newer it would be using the gallium
> > driver. Which I guess would need xAMBLE stuff wired up. Outside of
> > fd6_emit_restore() and fd6_gmem.cc there isn't really any state emit
> > in IB1, so I guess it probably wouldn't be too hard to get preemption
> > support wired up.
> >
> > BR,
> > -R
> >
> > > Unfortunately this is not easy to fix in Zink because it creates one
> > > VkDevice at screen creation and uses it for all GL contexts. Since GL
> > > priority is provided per context and at context creation time Zink has
> > > no way of handling this.
> > >
> > > Once TU will support more than one queue it will be possible for Zink to
> > > create one queue per priority then pick one at context creation time.
> > > Doing so would require a new vulkan extension for per queue global
> > > priority. I had started working on this some time ago
> > > https://gitlab.freedesktop.org/antonino/mesa/-/tree/priority_ext?ref_type=heads
> > > but this solution will only be viable once TU can expose more than one
> > > queue.
> > >
>
> Thanks, both of you for the clarification. Glad about the
> improvements planned for both freedreno and zink.
Only lightly tested so far, but
https://gitlab.freedesktop.org/robclark/mesa/-/tree/fd/a7xx-preemption?ref_type=heads
appears to work for getting preemption going on gl. Needs some
cleanup/etc, but if you want something with gl compositor supporting
preemption, you can give it a try
BR,
-R
> -Akhil.
>
> > > >
> > > > If possible it is a good idea to check the new preemption traces to
> > > > ensure preemption kicks in.
> > > >
> > > > -Akhil
> > > >
> > > >> Thanks,
> > > >> Neil
> > >
> > >
> > > Best regards,
> > > --
> > > Antonino Maniscalco <antomani103 at gmail.com>
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