On Thu, Apr 14, 2022 at 04:22:58PM +0000, Swinney, Jonathan wrote:
>  - ff_pix_abs16_neon
>  - ff_pix_abs16_xy2_neon
> 
> In direct micro benchmarks of these ff functions verses their C implementations,
> these functions performed as follows on AWS Graviton 2:
> 
> ff_pix_abs16_neon:
> c:  benchmark ran 100000 iterations in 0.955383 seconds
> ff: benchmark ran 100000 iterations in 0.097669 seconds
> 
> ff_pix_abs16_xy2_neon:
> c:  benchmark ran 100000 iterations in 1.916759 seconds
> ff: benchmark ran 100000 iterations in 0.370729 seconds
> 
> Signed-off-by: Jonathan Swinney <jswinney@amazon.com>
> ---
>  libavcodec/aarch64/Makefile              |   2 +
>  libavcodec/aarch64/me_cmp_init_aarch64.c |  39 +++++
>  libavcodec/aarch64/me_cmp_neon.S         | 209 +++++++++++++++++++++++
>  libavcodec/me_cmp.c                      |   2 +
>  libavcodec/me_cmp.h                      |   1 +
>  libavcodec/x86/me_cmp.asm                |   7 +
>  libavcodec/x86/me_cmp_init.c             |   3 +
>  tests/checkasm/Makefile                  |   2 +-
>  tests/checkasm/checkasm.c                |   1 +
>  tests/checkasm/checkasm.h                |   1 +
>  tests/checkasm/motion.c                  | 155 +++++++++++++++++
>  11 files changed, 421 insertions(+), 1 deletion(-)
>  create mode 100644 libavcodec/aarch64/me_cmp_init_aarch64.c
>  create mode 100644 libavcodec/aarch64/me_cmp_neon.S
>  create mode 100644 tests/checkasm/motion.c
> 
[...]
> diff --git a/libavcodec/x86/me_cmp.asm b/libavcodec/x86/me_cmp.asm
> index ad06d485ab..f73b9f9161 100644
> --- a/libavcodec/x86/me_cmp.asm
> +++ b/libavcodec/x86/me_cmp.asm
> @@ -255,6 +255,7 @@ hadamard8x8_diff %+ SUFFIX:
>  
>      HSUM                         m0, m1, eax
>      and                         rax, 0xFFFF
> +    emms
>      ret
>  
>  hadamard8_16_wrapper 0, 14
> @@ -345,6 +346,7 @@ cglobal sse%1, 5,5,8, v, pix1, pix2, lsize, h
>  
>      HADDD     m7, m1
>      movd     eax, m7         ; return value
> +    emms
>      RET
>  %endmacro

on which arm chip did you test this ?


[...]
> diff --git a/libavcodec/x86/me_cmp_init.c b/libavcodec/x86/me_cmp_init.c
> index 9af911bb88..b330868a38 100644
> --- a/libavcodec/x86/me_cmp_init.c
> +++ b/libavcodec/x86/me_cmp_init.c
> @@ -186,6 +186,8 @@ static int vsad_intra16_mmx(MpegEncContext *v, uint8_t *pix, uint8_t *dummy,
>          : "r" (stride), "m" (h)
>          : "%ecx");
>  
> +    emms_c();
> +
>      return tmp & 0xFFFF;
>  }
>  #undef SUM
> @@ -418,6 +420,7 @@ static inline int sum_mmx(void)
>          "paddw %%mm0, %%mm6             \n\t"
>          "movd %%mm6, %0                 \n\t"
>          : "=r" (ret));
> +    emms_c();
>      return ret & 0xFFFF;
>  }

hmmm

Also before the patch 
checkasm: all 6153 tests passed
after it
checkasm: all 3198 tests passed

thats on a x86-64

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Complexity theory is the science of finding the exact solution to an
approximation. Benchmarking OTOH is finding an approximation of the exact