[FFmpeg-devel] [PATCH 00/21] aarch64: hevc: Add missing hevc_pel NEON functions

[Martin Storsjö]

On Tue, 26 Mar 2024, Jean-Baptiste Kempf wrote:

> On Mon, 25 Mar 2024, at 22:56, J. Dekker wrote:
>>> On Mon, 25 Mar 2024, Martin Storsjö wrote:
>>>
>>>> Since some time, we have pretty complete AArch64 NEON coverage
>>>> for the hevc decoder.
>>>>
>>>> However, some of these functions require the I8MM instruction set
>>>> extension, and many of them (but not all) lack a plain NEON
>>>> version.
>>>>
>>>> This patchset fills in a regular NEON version of all functions
>>>> where we have an I8MM function.
>>>>
>>>> For context; the I8MM instruction set extension is a mandatory
>>>> part of armv8.6-a. E.g. Apple M2, AWS Graviton 3 have it,
>>>> but Apple M1 and Ampere Altra don't.
>>>>
>>>> This patchset takes decoding of a 1080p HEVC clip from 402
>>>> fps to 649 fps on an Apple M1.
>>>>
>>>> Patch #2 also fixes a subtle bug in the existing implementation;
>>>> two functions relied on the contents on the stack, below the
>>>> stack pointer, being untouched within a function. If a signal
>>>> gets delivered, those parts of the stack could be clobbered.
>>>
>>> I know this is a bit short notice for a patchset of this size - but, would people be OK with merging this patchset before the impending 7.0 branch (which is made within the next 24h)?
>>>
>>> The patches pass all my tricky build configurations, they give a very non-negligible speedup on many common CPUs, and patch #2 fixes a real bug in the existing impleemntations. (A bug fix patch can of course be backported after the branch too, but performance optimizations aren't generally relevant for backporting.)
>>>
>>> // Martin
>>
>> Yes, please. I will tomorrow morning if you didn’t already push.
>
> +1

Thanks, I pushed this set now.

// Martin