diff mbox series

[FFmpeg-devel,2/5] lavc/aarch64: Add neon implementation for sse4

Message ID 20220816122016.64929-3-hum@semihalf.com
State New
Headers show
Series Provide neon implementation for me_cmp functions | expand

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andriy/make_fate_x86 success Make fate finished

Commit Message

Hubert Mazur Aug. 16, 2022, 12:20 p.m. UTC 
Provide neon implementation for sse4 function.

Performance comparison tests are shown below.
- sse_2_c: 80.7
- sse_2_neon: 31.0

Benchmarks and tests are run with checkasm tool on AWS Graviton 3.

Signed-off-by: Hubert Mazur <hum@semihalf.com>
---
 libavcodec/aarch64/me_cmp_init_aarch64.c |  3 ++
 libavcodec/aarch64/me_cmp_neon.S         | 58 ++++++++++++++++++++++++
 2 files changed, 61 insertions(+)

Comments

Martin Storsjö Aug. 18, 2022, 9:10 a.m. UTC | #1 
On Tue, 16 Aug 2022, Hubert Mazur wrote:

> Provide neon implementation for sse4 function.
>
> Performance comparison tests are shown below.
> - sse_2_c: 80.7
> - sse_2_neon: 31.0
>
> Benchmarks and tests are run with checkasm tool on AWS Graviton 3.
>
> Signed-off-by: Hubert Mazur <hum@semihalf.com>
> ---
> libavcodec/aarch64/me_cmp_init_aarch64.c |  3 ++
> libavcodec/aarch64/me_cmp_neon.S         | 58 ++++++++++++++++++++++++
> 2 files changed, 61 insertions(+)

This patch had the same issue about unused d18 register and unnecessary 
add instruction, and the misaligned function declaration.

// Martin
diff mbox series

Patch

diff --git a/libavcodec/aarch64/me_cmp_init_aarch64.c b/libavcodec/aarch64/me_cmp_init_aarch64.c
index 7780009d41..955592625a 100644
--- a/libavcodec/aarch64/me_cmp_init_aarch64.c
+++ b/libavcodec/aarch64/me_cmp_init_aarch64.c
@@ -32,6 +32,8 @@  int ff_pix_abs16_x2_neon(MpegEncContext *v, const uint8_t *pix1, const uint8_t *
 
 int sse16_neon(MpegEncContext *v, const uint8_t *pix1, const uint8_t *pix2,
                       ptrdiff_t stride, int h);
+int sse4_neon(MpegEncContext *v, const uint8_t *pix1, const uint8_t *pix2,
+                      ptrdiff_t stride, int h);
 
 av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx)
 {
@@ -44,5 +46,6 @@  av_cold void ff_me_cmp_init_aarch64(MECmpContext *c, AVCodecContext *avctx)
 
         c->sad[0] = ff_pix_abs16_neon;
         c->sse[0] = sse16_neon;
+        c->sse[2] = sse4_neon;
     }
 }
diff --git a/libavcodec/aarch64/me_cmp_neon.S b/libavcodec/aarch64/me_cmp_neon.S
index 825ce45d13..367924b3c2 100644
--- a/libavcodec/aarch64/me_cmp_neon.S
+++ b/libavcodec/aarch64/me_cmp_neon.S
@@ -346,3 +346,61 @@  function sse16_neon, export=1
 
         ret
 endfunc
+
+function sse4_neon, export=1
+        // x0 - unused
+        // x1 - pix1
+        // x2 - pix2
+        // x3 - stride
+        // w4 - h
+
+        movi            d18, #0
+        movi            v16.4s, #0                      // clear the result accumulator
+        cmp             w4, #4
+        b.le            2f
+
+// make 4 iterations at once
+1:
+
+        // res = abs(pix1[0] - pix2[0])
+        // res * res
+
+        ld1             {v0.s}[0], [x1], x3             // Load pix1, first iteration
+        ld1             {v1.s}[0], [x2], x3             // Load pix2, first iteration
+        ld1             {v2.s}[0], [x1], x3             // Load pix1, second iteration
+        ld1             {v3.s}[0], [x2], x3             // Load pix2, second iteration
+        uabdl           v30.8h, v0.8b, v1.8b            // Absolute difference, first iteration
+        ld1             {v4.s}[0], [x1], x3             // Load pix1, third iteration
+        ld1             {v5.s}[0], [x2], x3             // Load pix2, third iteration
+        uabdl           v29.8h, v2.8b, v3.8b            // Absolute difference, second iteration
+        umlal           v16.4s, v30.4h, v30.4h          // Multiply vectors, first iteration
+        ld1             {v6.s}[0], [x1], x3             // Load pix1, fourth iteration
+        ld1             {v7.s}[0], [x2], x3             // Load pix2, fourth iteration
+        uabdl           v28.8h, v4.8b, v5.8b            // Absolute difference, third iteration
+        umlal           v16.4s, v29.4h, v29.4h          // Multiply and accumulate, second iteration
+        sub             w4, w4, #4
+        uabdl           v27.8h, v6.8b, v7.8b            // Absolue difference, fourth iteration
+        umlal           v16.4s, v28.4h, v28.4h          // Multiply and accumulate, third iteration
+        cmp             w4, #4
+        umlal           v16.4s, v27.4h, v27.4h          // Multiply and accumulate, fourth iteration
+        b.ge            1b
+
+        cbz             w4, 3f
+
+// iterate by one
+2:
+        ld1             {v0.s}[0], [x1], x3               // Load pix1
+        ld1             {v1.s}[0], [x2], x3               // Load pix2
+        uabdl           v30.8h, v0.8b, v1.8b
+        subs            w4, w4, #1
+        umlal           v16.4s, v30.4h, v30.4h
+
+        b.ne            2b
+
+3:
+        uaddlv          d17, v16.4s                     // Add vector
+        add             d18, d18, d17
+        fmov            w0, s18
+
+        ret
+endfunc