[FFmpeg-devel] [PATCH] Moves yuv2yuvX_sse3 to yasm, unrolls main loop and other small optimizations for ~20% speedup. AVX2 version is ready and tested, although local tests show a significant speed-up in this function using avx2, swscale code slows down overall probably due cpu frequency scaling.

Alan Kelly alankelly at google.com
Thu Oct 22 10:43:53 EEST 2020


Other functions to be ported to avx2 have been identified and are on
the todo list.
---
 libswscale/x86/Makefile     |   1 +
 libswscale/x86/swscale.c    |  72 +++----------------------
 libswscale/x86/yuv2yuvX.asm | 105 ++++++++++++++++++++++++++++++++++++
 3 files changed, 112 insertions(+), 66 deletions(-)
 create mode 100644 libswscale/x86/yuv2yuvX.asm

diff --git a/libswscale/x86/Makefile b/libswscale/x86/Makefile
index 831d5359aa..bfe383364e 100644
--- a/libswscale/x86/Makefile
+++ b/libswscale/x86/Makefile
@@ -13,3 +13,4 @@ X86ASM-OBJS                     += x86/input.o                          \
                                    x86/scale.o                          \
                                    x86/rgb_2_rgb.o                      \
                                    x86/yuv_2_rgb.o                      \
+                                   x86/yuv2yuvX.o                       \
diff --git a/libswscale/x86/swscale.c b/libswscale/x86/swscale.c
index 3160fedf04..ea83b097ca 100644
--- a/libswscale/x86/swscale.c
+++ b/libswscale/x86/swscale.c
@@ -197,6 +197,10 @@ void ff_updateMMXDitherTables(SwsContext *c, int dstY)
 }
 
 #if HAVE_MMXEXT
+void ff_yuv2yuvX_sse3(const int16_t *filter, int filterSize,
+                           uint8_t *dest, int dstW,
+                           const uint8_t *dither, int offset);
+
 static void yuv2yuvX_sse3(const int16_t *filter, int filterSize,
                            const int16_t **src, uint8_t *dest, int dstW,
                            const uint8_t *dither, int offset)
@@ -205,72 +209,8 @@ static void yuv2yuvX_sse3(const int16_t *filter, int filterSize,
         yuv2yuvX_mmxext(filter, filterSize, src, dest, dstW, dither, offset);
         return;
     }
-    filterSize--;
-#define MAIN_FUNCTION \
-        "pxor       %%xmm0, %%xmm0 \n\t" \
-        "punpcklbw  %%xmm0, %%xmm3 \n\t" \
-        "movd           %4, %%xmm1 \n\t" \
-        "punpcklwd  %%xmm1, %%xmm1 \n\t" \
-        "punpckldq  %%xmm1, %%xmm1 \n\t" \
-        "punpcklqdq %%xmm1, %%xmm1 \n\t" \
-        "psllw          $3, %%xmm1 \n\t" \
-        "paddw      %%xmm1, %%xmm3 \n\t" \
-        "psraw          $4, %%xmm3 \n\t" \
-        "movdqa     %%xmm3, %%xmm4 \n\t" \
-        "movdqa     %%xmm3, %%xmm7 \n\t" \
-        "movl           %3, %%ecx  \n\t" \
-        "mov                                 %0, %%"FF_REG_d"        \n\t"\
-        "mov                        (%%"FF_REG_d"), %%"FF_REG_S"     \n\t"\
-        ".p2align                             4             \n\t" /* FIXME Unroll? */\
-        "1:                                                 \n\t"\
-        "movddup                  8(%%"FF_REG_d"), %%xmm0   \n\t" /* filterCoeff */\
-        "movdqa              (%%"FF_REG_S", %%"FF_REG_c", 2), %%xmm2 \n\t" /* srcData */\
-        "movdqa            16(%%"FF_REG_S", %%"FF_REG_c", 2), %%xmm5 \n\t" /* srcData */\
-        "add                                $16, %%"FF_REG_d"        \n\t"\
-        "mov                        (%%"FF_REG_d"), %%"FF_REG_S"     \n\t"\
-        "test                         %%"FF_REG_S", %%"FF_REG_S"     \n\t"\
-        "pmulhw                           %%xmm0, %%xmm2      \n\t"\
-        "pmulhw                           %%xmm0, %%xmm5      \n\t"\
-        "paddw                            %%xmm2, %%xmm3      \n\t"\
-        "paddw                            %%xmm5, %%xmm4      \n\t"\
-        " jnz                                1b             \n\t"\
-        "psraw                               $3, %%xmm3      \n\t"\
-        "psraw                               $3, %%xmm4      \n\t"\
-        "packuswb                         %%xmm4, %%xmm3      \n\t"\
-        "movntdq                          %%xmm3, (%1, %%"FF_REG_c") \n\t"\
-        "add                         $16, %%"FF_REG_c"        \n\t"\
-        "cmp                          %2, %%"FF_REG_c"        \n\t"\
-        "movdqa                   %%xmm7, %%xmm3            \n\t" \
-        "movdqa                   %%xmm7, %%xmm4            \n\t" \
-        "mov                                 %0, %%"FF_REG_d"        \n\t"\
-        "mov                        (%%"FF_REG_d"), %%"FF_REG_S"     \n\t"\
-        "jb                                  1b             \n\t"
-
-    if (offset) {
-        __asm__ volatile(
-            "movq          %5, %%xmm3  \n\t"
-            "movdqa    %%xmm3, %%xmm4  \n\t"
-            "psrlq        $24, %%xmm3  \n\t"
-            "psllq        $40, %%xmm4  \n\t"
-            "por       %%xmm4, %%xmm3  \n\t"
-            MAIN_FUNCTION
-              :: "g" (filter),
-              "r" (dest-offset), "g" ((x86_reg)(dstW+offset)), "m" (offset),
-              "m"(filterSize), "m"(((uint64_t *) dither)[0])
-              : XMM_CLOBBERS("%xmm0" , "%xmm1" , "%xmm2" , "%xmm3" , "%xmm4" , "%xmm5" , "%xmm7" ,)
-                "%"FF_REG_d, "%"FF_REG_S, "%"FF_REG_c
-              );
-    } else {
-        __asm__ volatile(
-            "movq          %5, %%xmm3   \n\t"
-            MAIN_FUNCTION
-              :: "g" (filter),
-              "r" (dest-offset), "g" ((x86_reg)(dstW+offset)), "m" (offset),
-              "m"(filterSize), "m"(((uint64_t *) dither)[0])
-              : XMM_CLOBBERS("%xmm0" , "%xmm1" , "%xmm2" , "%xmm3" , "%xmm4" , "%xmm5" , "%xmm7" ,)
-                "%"FF_REG_d, "%"FF_REG_S, "%"FF_REG_c
-              );
-    }
+    ff_yuv2yuvX_sse3(filter, filterSize - 1, dest - offset, dstW + offset, dither, offset);
+    return;
 }
 #endif
 
diff --git a/libswscale/x86/yuv2yuvX.asm b/libswscale/x86/yuv2yuvX.asm
new file mode 100644
index 0000000000..0f1fa12326
--- /dev/null
+++ b/libswscale/x86/yuv2yuvX.asm
@@ -0,0 +1,105 @@
+;******************************************************************************
+;* x86-optimized yuv2yuvX
+;* Copyright 2020 Google LLC
+;*
+;* This file is part of FFmpeg.
+;*
+;* FFmpeg is free software; you can redistribute it and/or
+;* modify it under the terms of the GNU Lesser General Public
+;* License as published by the Free Software Foundation; either
+;* version 2.1 of the License, or (at your option) any later version.
+;*
+;* FFmpeg is distributed in the hope that it will be useful,
+;* but WITHOUT ANY WARRANTY; without even the implied warranty of
+;* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+;* Lesser General Public License for more details.
+;*
+;* You should have received a copy of the GNU Lesser General Public
+;* License along with FFmpeg; if not, write to the Free Software
+;* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+;******************************************************************************
+
+%include "libavutil/x86/x86util.asm"
+
+SECTION .text
+
+;-----------------------------------------------------------------------------
+; yuv2yuvX
+;
+; void ff_yuv2yuvX_<opt>(const int16_t *filter, int filterSize,
+;                        uint8_t *dest, int dstW,
+;                        const uint8_t *dither, int offset);
+;
+;-----------------------------------------------------------------------------
+
+%macro YUV2YUVX_FUNC 0
+cglobal yuv2yuvX, 6, 7, 16, filter, rsi, dest, dstW, dither, offset, src
+%if ARCH_X86_64
+    movsxd               dstWq, dstWd
+    movsxd               offsetq, offsetd
+%endif ; x86-64
+    movq                 xmm3, [ditherq]
+    cmp                  offsetd, 0
+    jz                   .offset
+
+    ; offset != 0 path.
+    psrlq                m5, m3, $18
+    psllq                m3, m3, $28
+    por                  m3, m3, m5
+
+.offset:
+%if cpuflag(avx2)
+    vperm2i128           m3, m3, m3, 0
+%endif ; avx2
+%if ARCH_X86_64
+    movq                 xmm1, rsiq
+%else
+    movd                 mm1, rsi
+%endif
+    vpbroadcastw         m1, xmm1
+    pxor                 m0, m0, m0
+    mov                  rsiq, filterq
+    mov                  srcq, [rsiq]
+    punpcklbw            m3, m0
+    psllw                m1, m1, 3
+    paddw                m3, m3, m1
+    psraw                m7, m3, 4
+.outerloop:
+    mova                 m4, m7
+    mova                 m3, m7
+    mova                 m6, m7
+    mova                 m1, m7
+.loop:
+    vpbroadcastq         m0, [rsiq + 8]
+    pmulhw               m2, m0, [srcq + offsetq * 2]
+    pmulhw               m5, m0, [srcq + offsetq * 2 + mmsize]
+    paddw                m3, m3, m2
+    paddw                m4, m4, m5
+    pmulhw               m2, m0, [srcq + offsetq * 2 + 2 * mmsize]
+    pmulhw               m5, m0, [srcq + offsetq * 2 + 3 * mmsize]
+    paddw                m6, m6, m2
+    paddw                m1, m1, m5
+    add                  rsiq, $10
+    mov                  srcq, [rsiq]
+    test                 srcd, srcd
+    jnz                  .loop
+    psraw                m3, m3, 3
+    psraw                m4, m4, 3
+    psraw                m6, m6, 3
+    psraw                m1, m1, 3
+    packuswb             m3, m3, m4
+    packuswb             m6, m6, m1
+    mov                  srcq, [filterq]
+    movntdq              [destq + offsetq], m3
+    movntdq              [destq + offsetq + mmsize], m6
+    add                  offsetq, mmsize
+    mov                  rsiq, filterq
+    cmp                  offsetq, dstWq
+    jb                  .outerloop
+    REP_RET
+%endmacro
+
+INIT_XMM sse3
+YUV2YUVX_FUNC
+INIT_YMM avx2
+YUV2YUVX_FUNC
-- 
2.29.0.rc1.297.gfa9743e501-goog



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