On Mon, 25 Jul 2022, Hubert Mazur wrote:
Provide optimized implementation of pix_abs8 function for arm64.Performance comparison tests are shown below. - pix_abs_1_0_c: 105.2 - pix_abs_1_0_neon: 21.4 - sad_1_c: 107.2 - sad_1_neon: 20.9 Benchmarks and tests are run with checkasm tool on AWS Graviton 3. --- libavcodec/aarch64/me_cmp_init_aarch64.c | 4 ++ libavcodec/aarch64/me_cmp_neon.S | 53 ++++++++++++++++++++++++ 2 files changed, 57 insertions(+) diff --git a/libavcodec/aarch64/me_cmp_init_aarch64.c b/libavcodec/aarch64/me_cmp_init_aarch64.c index 89c817990c..7d7dc38754 100644 --- a/libavcodec/aarch64/me_cmp_init_aarch64.c +++ b/libavcodec/aarch64/me_cmp_init_aarch64.c @@ -31,6 +31,8 @@ int ff_pix_abs16_x2_neon(MpegEncContext *v, uint8_t *pix1, uint8_t *pix2, ptrdiff_t stride, int h); int ff_pix_abs16_y2_neon(MpegEncContext *v, uint8_t *pix1, uint8_t *pix2, ptrdiff_t stride, int h); +int ff_pix_abs8_neon(MpegEncContext *s, uint8_t *blk1, uint8_t *blk2, + ptrdiff_t stride, int h); int sse16_neon(MpegEncContext *v, uint8_t *pix1, uint8_t *pix2, ptrdiff_t stride, int h); @@ -48,8 +50,10 @@ av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx) c->pix_abs[0][1] = ff_pix_abs16_x2_neon; c->pix_abs[0][2] = ff_pix_abs16_y2_neon; c->pix_abs[0][3] = ff_pix_abs16_xy2_neon; + c->pix_abs[1][0] = ff_pix_abs8_neon; c->sad[0] = ff_pix_abs16_neon; + c->sad[1] = ff_pix_abs8_neon; c->sse[0] = sse16_neon; c->sse[1] = sse8_neon; c->sse[2] = sse4_neon; diff --git a/libavcodec/aarch64/me_cmp_neon.S b/libavcodec/aarch64/me_cmp_neon.S index dcaffc9b73..f2dd63ced1 100644 --- a/libavcodec/aarch64/me_cmp_neon.S +++ b/libavcodec/aarch64/me_cmp_neon.S @@ -72,6 +72,59 @@ function ff_pix_abs16_neon, export=1 ret endfunc +function ff_pix_abs8_neon, export=1 + // x0 unused + // x1 uint8_t *pix1 + // x2 uint8_t *pix2 + // x3 ptrdiff_t stride + // x4 int h + + movi d18, #0 + cmp w4, #4 + b.lt 2f + +// make 4 iterations at once +1: + ld1 {v0.8b}, [x1], x3 // Load pix1 for first iteration + ld1 {v1.8b}, [x2], x3 // Load pix2 for first iteration + uabdl v30.8h, v0.8b, v1.8b // Absolute difference, first iteration + ld1 {v2.8b}, [x1], x3 // Load pix1 for second iteration + ld1 {v3.8b}, [x2], x3 // Load pix2 for second iteration + uabal v30.8h, v2.8b, v3.8b // Absolute difference, second iteration + ld1 {v4.8b}, [x1], x3 // Load pix1 for third iteration + ld1 {v5.8b}, [x2], x3 // Load pix2 for third iteration + uabal v30.8h, v4.8b, v5.8b // Absolute difference, third iteration + ld1 {v6.8b}, [x1], x3 // Load pix1 for foruth iteration + ld1 {v7.8b}, [x2], x3 // Load pix2 for fourth iteration + uabal v30.8h, v6.8b, v7.8b // Absolute difference, foruth iteration
This is maybe the simplest example so far, where the unrolled version here just is 4 identical serial copies of the same set of 3 instructions; this maybe helps a bit on some CPUs, but it doesn't help nearly as much as it can on others, if it would be better unrolled.
I.e., same comments as for the other patches; improve interleaving, don't do uaddlv once per iteration.
// 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".
