On Tue, 6 Sep 2022, Hubert Mazur wrote:
Provide optimized implementation of vsse16 for arm64.Performance comparison tests are shown below. - vsse_0_c: 254.4 - vsse_0_neon: 64.7 Benchmarks and tests are run with checkasm tool on AWS Graviton 3. Signed-off-by: Hubert Mazur <h...@semihalf.com> --- libavcodec/aarch64/me_cmp_init_aarch64.c | 4 ++ libavcodec/aarch64/me_cmp_neon.S | 87 ++++++++++++++++++++++++ 2 files changed, 91 insertions(+) diff --git a/libavcodec/aarch64/me_cmp_init_aarch64.c b/libavcodec/aarch64/me_cmp_init_aarch64.c index ddc5d05611..7b81e48d16 100644 --- a/libavcodec/aarch64/me_cmp_init_aarch64.c +++ b/libavcodec/aarch64/me_cmp_init_aarch64.c @@ -43,6 +43,8 @@ int sse4_neon(MpegEncContext *v, const uint8_t *pix1, const uint8_t *pix2, int vsad16_neon(MpegEncContext *c, const uint8_t *s1, const uint8_t *s2, ptrdiff_t stride, int h); +int vsse16_neon(MpegEncContext *c, const uint8_t *s1, const uint8_t *s2, + ptrdiff_t stride, int h); av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx) { @@ -62,5 +64,7 @@ av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx) c->sse[2] = sse4_neon; c->vsad[0] = vsad16_neon; + + c->vsse[0] = vsse16_neon; } } diff --git a/libavcodec/aarch64/me_cmp_neon.S b/libavcodec/aarch64/me_cmp_neon.S index 1d0b166d69..b3f376aa60 100644 --- a/libavcodec/aarch64/me_cmp_neon.S +++ b/libavcodec/aarch64/me_cmp_neon.S @@ -649,3 +649,90 @@ function vsad16_neon, export=1 ret endfunc + +function vsse16_neon, export=1 + // x0 unused + // x1 uint8_t *pix1 + // x2 uint8_t *pix2 + // x3 ptrdiff_t stride + // w4 int h + + ld1 {v0.16b}, [x1], x3 // Load pix1[0], first iteration + ld1 {v1.16b}, [x2], x3 // Load pix2[0], first iteration + + sub w4, w4, #1 // we need to make h-1 iterations + movi v16.4s, #0 + movi v17.4s, #0 + + cmp w4, #3 // check if we can make 3 iterations at once + usubl v31.8h, v0.8b, v1.8b // Signed difference of pix1[0] - pix2[0], first iteration + usubl2 v30.8h, v0.16b, v1.16b // Signed difference of pix1[0] - pix2[0], first iteration + b.le 2f + + +1: + // x = abs(pix1[0] - pix2[0] - pix1[0 + stride] + pix2[0 + stride]) + // res = (x) * (x)
Technically, there's no need for abs() here, we can just as well just do a plain subtraction. I tested this by replacing sabd with sub here (and changing umlal into smlal). It doesn't make any difference for the performance on the cores I tested on though - apparently there's no difference in performance between sabd and sub. So in practice, both should be fine. And I don't think that either of them is better for handling overflows/edge cases here either (which shouldn't be happening anyway).
// Martin _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
