Re: [PATCH v10 00/15] dma-fence: Deadline awareness

[Rob Clark]

On Wed, Mar 8, 2023 at 7:53 AM Rob Clark <robdclark@xxxxxxxxx> wrote:
>
> From: Rob Clark <robdclark@xxxxxxxxxxxx>
>
> This series adds a deadline hint to fences, so realtime deadlines
> such as vblank can be communicated to the fence signaller for power/
> frequency management decisions.
>
> This is partially inspired by a trick i915 does, but implemented
> via dma-fence for a couple of reasons:
>
> 1) To continue to be able to use the atomic helpers
> 2) To support cases where display and gpu are different drivers
>
> This iteration adds a dma-fence ioctl to set a deadline (both to
> support igt-tests, and compositors which delay decisions about which
> client buffer to display), and a sw_sync ioctl to read back the
> deadline.  IGT tests utilizing these can be found at:
>
>   https://gitlab.freedesktop.org/robclark/igt-gpu-tools/-/commits/fence-deadline
>

jfwiw, mesa side of this:

https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/21973

BR,
-R

>
> v1: https://patchwork.freedesktop.org/series/93035/
> v2: Move filtering out of later deadlines to fence implementation
>     to avoid increasing the size of dma_fence
> v3: Add support in fence-array and fence-chain; Add some uabi to
>     support igt tests and userspace compositors.
> v4: Rebase, address various comments, and add syncobj deadline
>     support, and sync_file EPOLLPRI based on experience with perf/
>     freq issues with clvk compute workloads on i915 (anv)
> v5: Clarify that this is a hint as opposed to a more hard deadline
>     guarantee, switch to using u64 ns values in UABI (still absolute
>     CLOCK_MONOTONIC values), drop syncobj related cap and driver
>     feature flag in favor of allowing count_handles==0 for probing
>     kernel support.
> v6: Re-work vblank helper to calculate time of _start_ of vblank,
>     and work correctly if the last vblank event was more than a
>     frame ago.  Add (mostly unrelated) drm/msm patch which also
>     uses the vblank helper.  Use dma_fence_chain_contained().  More
>     verbose syncobj UABI comments.  Drop DMA_FENCE_FLAG_HAS_DEADLINE_BIT.
> v7: Fix kbuild complaints about vblank helper.  Add more docs.
> v8: Add patch to surface sync_file UAPI, and more docs updates.
> v9: Drop (E)POLLPRI support.. I still like it, but not essential and
>     it can always be revived later.  Fix doc build warning.
> v10: Update 11/15 to handle multiple CRTCs
>
> Rob Clark (15):
>   dma-buf/dma-fence: Add deadline awareness
>   dma-buf/fence-array: Add fence deadline support
>   dma-buf/fence-chain: Add fence deadline support
>   dma-buf/dma-resv: Add a way to set fence deadline
>   dma-buf/sync_file: Surface sync-file uABI
>   dma-buf/sync_file: Add SET_DEADLINE ioctl
>   dma-buf/sw_sync: Add fence deadline support
>   drm/scheduler: Add fence deadline support
>   drm/syncobj: Add deadline support for syncobj waits
>   drm/vblank: Add helper to get next vblank time
>   drm/atomic-helper: Set fence deadline for vblank
>   drm/msm: Add deadline based boost support
>   drm/msm: Add wait-boost support
>   drm/msm/atomic: Switch to vblank_start helper
>   drm/i915: Add deadline based boost support
>
> Rob Clark (15):
>   dma-buf/dma-fence: Add deadline awareness
>   dma-buf/fence-array: Add fence deadline support
>   dma-buf/fence-chain: Add fence deadline support
>   dma-buf/dma-resv: Add a way to set fence deadline
>   dma-buf/sync_file: Surface sync-file uABI
>   dma-buf/sync_file: Add SET_DEADLINE ioctl
>   dma-buf/sw_sync: Add fence deadline support
>   drm/scheduler: Add fence deadline support
>   drm/syncobj: Add deadline support for syncobj waits
>   drm/vblank: Add helper to get next vblank time
>   drm/atomic-helper: Set fence deadline for vblank
>   drm/msm: Add deadline based boost support
>   drm/msm: Add wait-boost support
>   drm/msm/atomic: Switch to vblank_start helper
>   drm/i915: Add deadline based boost support
>
>  Documentation/driver-api/dma-buf.rst    | 16 ++++-
>  drivers/dma-buf/dma-fence-array.c       | 11 ++++
>  drivers/dma-buf/dma-fence-chain.c       | 12 ++++
>  drivers/dma-buf/dma-fence.c             | 60 ++++++++++++++++++
>  drivers/dma-buf/dma-resv.c              | 22 +++++++
>  drivers/dma-buf/sw_sync.c               | 81 +++++++++++++++++++++++++
>  drivers/dma-buf/sync_debug.h            |  2 +
>  drivers/dma-buf/sync_file.c             | 19 ++++++
>  drivers/gpu/drm/drm_atomic_helper.c     | 37 +++++++++++
>  drivers/gpu/drm/drm_syncobj.c           | 64 +++++++++++++++----
>  drivers/gpu/drm/drm_vblank.c            | 53 +++++++++++++---
>  drivers/gpu/drm/i915/i915_request.c     | 20 ++++++
>  drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 15 -----
>  drivers/gpu/drm/msm/msm_atomic.c        |  8 ++-
>  drivers/gpu/drm/msm/msm_drv.c           | 12 ++--
>  drivers/gpu/drm/msm/msm_fence.c         | 74 ++++++++++++++++++++++
>  drivers/gpu/drm/msm/msm_fence.h         | 20 ++++++
>  drivers/gpu/drm/msm/msm_gem.c           |  5 ++
>  drivers/gpu/drm/msm/msm_kms.h           |  8 ---
>  drivers/gpu/drm/scheduler/sched_fence.c | 46 ++++++++++++++
>  drivers/gpu/drm/scheduler/sched_main.c  |  2 +-
>  include/drm/drm_vblank.h                |  1 +
>  include/drm/gpu_scheduler.h             | 17 ++++++
>  include/linux/dma-fence.h               | 22 +++++++
>  include/linux/dma-resv.h                |  2 +
>  include/uapi/drm/drm.h                  | 17 ++++++
>  include/uapi/drm/msm_drm.h              | 14 ++++-
>  include/uapi/linux/sync_file.h          | 59 +++++++++++-------
>  28 files changed, 640 insertions(+), 79 deletions(-)
>
> --
> 2.39.2
>