[PATCH v9 00/15] dma-fence: Deadline awareness

Rob Clark
2023-03-02T23:54:05Z

From: Rob Clark <robdclark@chromium.org>

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

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.

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 | 36 +++++++++++
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, 639 insertions(+), 79 deletions(-)

--
2.39.1