From 3e708722a2d06b8c7290d359ccaea9cd9885e701 Mon Sep 17 00:00:00 2001 From: "Swinney, Jonathan" Date: Sat, 13 Aug 2022 20:56:02 +0000 Subject: [PATCH] swscale/aarch64: vscale optimization MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Use scalar times vector multiply accumlate instructions instead of vector times vector to remove the need for replicating load instructions which are slightly slower. On AWS c7g (Graviton 3, Neoverse V1) instances: yuv2yuvX_8_0_512_accurate_neon: 1144.8 987.4 yuv2yuvX_16_0_512_accurate_neon: 2080.5 1869.4 Signed-off-by: Jonathan Swinney Signed-off-by: Martin Storsjö --- libswscale/aarch64/output.S | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/libswscale/aarch64/output.S b/libswscale/aarch64/output.S index af71de6050..991750cf31 100644 --- a/libswscale/aarch64/output.S +++ b/libswscale/aarch64/output.S @@ -34,16 +34,15 @@ function ff_yuv2planeX_8_neon, export=1 mov x9, x2 // srcp = src mov x10, x0 // filterp = filter 3: ldp x11, x12, [x9], #16 // get 2 pointers: src[j] and src[j+1] + ldr s7, [x10], #4 // read 2x16-bit coeff X and Y at filter[j] and filter[j+1] add x11, x11, x7, lsl #1 // &src[j ][i] add x12, x12, x7, lsl #1 // &src[j+1][i] ld1 {v5.8H}, [x11] // read 8x16-bit @ src[j ][i + {0..7}]: A,B,C,D,E,F,G,H ld1 {v6.8H}, [x12] // read 8x16-bit @ src[j+1][i + {0..7}]: I,J,K,L,M,N,O,P - ld1r {v7.8H}, [x10], #2 // read 1x16-bit coeff X at filter[j ] and duplicate across lanes - ld1r {v16.8H}, [x10], #2 // read 1x16-bit coeff Y at filter[j+1] and duplicate across lanes - smlal v3.4S, v5.4H, v7.4H // val0 += {A,B,C,D} * X - smlal2 v4.4S, v5.8H, v7.8H // val1 += {E,F,G,H} * X - smlal v3.4S, v6.4H, v16.4H // val0 += {I,J,K,L} * Y - smlal2 v4.4S, v6.8H, v16.8H // val1 += {M,N,O,P} * Y + smlal v3.4S, v5.4H, v7.H[0] // val0 += {A,B,C,D} * X + smlal2 v4.4S, v5.8H, v7.H[0] // val1 += {E,F,G,H} * X + smlal v3.4S, v6.4H, v7.H[1] // val0 += {I,J,K,L} * Y + smlal2 v4.4S, v6.8H, v7.H[1] // val1 += {M,N,O,P} * Y subs w8, w8, #2 // tmpfilterSize -= 2 b.gt 3b // loop until filterSize consumed