[x265] [arm64] port filterPixelToShort

[chen]

You are welcome.
on your CPU, the ldp still slower, so we can keep origin version and improve it again in future.
This version looks good for me, thank you for your contribute.



At 2021-06-24 10:01:40, "Pop, Sebastian" <spop at amazon.com> wrote:

Thanks again Chen for your careful review and recommendations.

 

I added the following change to the attached patch as we get better performance:

 

--- a/source/common/aarch64/ipfilter8.S

+++ b/source/common/aarch64/ipfilter8.S

@@ -35,14 +35,14 @@ function x265_filterPixelToShort_4x4_neon

     movi            v2.8h, #0xe0, lsl #8

     ld1             {v0.s}[0], [x0], x1

     ld1             {v0.s}[1], [x0], x1

-    ld1             {v1.s}[2], [x0], x1

-    ld1             {v1.s}[3], [x0], x1

     ushll           v3.8h, v0.8b, #6

-    ushll2          v4.8h, v1.16b, #6

     add             v3.8h, v3.8h, v2.8h

-    add             v4.8h, v4.8h, v2.8h

     st1             {v3.d}[0], [x2], x3

     st1             {v3.d}[1], [x2], x3

+    ld1             {v1.s}[0], [x0], x1

+    ld1             {v1.s}[1], [x0], x1

+    ushll           v4.8h, v1.8b, #6

+    add             v4.8h, v4.8h, v2.8h

     st1             {v4.d}[0], [x2], x3

     st1             {v4.d}[1], [x2], x3

     ret

 

Before:

convert_p2s[  4x4]                           1.20x      4.99      6.01

 

After:

convert_p2s[  4x4]                           1.38x      4.20      5.78

 

I tried the ldp with post-increment as you recommended.

Performance is slightly lower with the change:

 

function x265_filterPixelToShort_64x\h\()_neon

     add             x3, x3, x3

     sub             x3, x3, #0x40

+    sub             x1, x1, #0x20

     movi            v4.8h, #0xe0, lsl #8

     mov             x9, #\r

.loop_filterP2S_64x\h:

     subs            x9, x9, #1

.rept 2

-    ld1             {v0.16b-v3.16b}, [x0], x1

+    ldp             q0, q1, [x0], #0x20

+    ldp             q0, q1, [x0]

+    add             x0, x0, x1

     ushll           v16.8h, v0.8b, #6

     ushll2          v17.8h, v0.16b, #6

     ushll           v18.8h, v1.8b, #6

 

Before:

convert_p2s[64x16]                        1.46x      105.52                  154.47

convert_p2s[64x32]                        1.47x      212.06                  312.14

convert_p2s[64x48]                        1.47x      318.75                  467.61

convert_p2s[64x64]                        1.46x      425.61                  622.36

 

After:

convert_p2s[64x16]                        1.42x      108.41                  154.37

convert_p2s[64x32]                        1.45x      215.18                  312.12

convert_p2s[64x48]                        1.44x      325.01                  468.76

convert_p2s[64x64]                        1.44x      432.46                  622.36

 
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