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

Pekka Paalanen ppaalanen at gmail.com
Thu Mar 9 10:21:18 UTC 2023


On Wed,  8 Mar 2023 07:52:51 -0800
Rob Clark <robdclark at gmail.com> wrote:

> From: Rob Clark <robdclark at 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.
> v10: Update 11/15 to handle multiple CRTCs

Hi Rob,

it is very nice to keep revision numbers and list the changes in each
patch. If I looked at series v8 last, and I now see series v10, and I
look at a patch that lists changes done in v7, how do I know if that
change was made between series v8 and v10 or earlier?

At least in some previous revision, series might have been v8 and a
patch have new changes listed as v5 (because it was the 5th time that
one patch was changed) instead of v8.

Am I expected to keep track of vN of each individual patch
independently?


Thanks,
pq
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