[FFmpeg-devel] [PATCH] Moves yuv2yuvX_sse3 to yasm, unrolls main loop and other small optimizations for ~20% speedup.

Alan Kelly alankelly at google.com
Tue Jan 5 14:31:25 EET 2021


Ping!

On Thu, Dec 17, 2020 at 11:42 AM Alan Kelly <alankelly at google.com> wrote:

> ---
>  Fixes memory alignment problem in checkasm-sw_scale
>  Tested on Linux 32 and 64 bit and mingw32
>  libswscale/x86/Makefile     |   1 +
>  libswscale/x86/swscale.c    | 106 +++++++++-----------------------
>  libswscale/x86/yuv2yuvX.asm | 117 ++++++++++++++++++++++++++++++++++++
>  tests/checkasm/sw_scale.c   |  98 ++++++++++++++++++++++++++++++
>  4 files changed, 246 insertions(+), 76 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..8cd8713705 100644
> --- a/libswscale/x86/swscale.c
> +++ b/libswscale/x86/swscale.c
> @@ -197,81 +197,30 @@ void ff_updateMMXDitherTables(SwsContext *c, int
> dstY)
>  }
>
>  #if HAVE_MMXEXT
> -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)
> -{
> -    if(((uintptr_t)dest) & 15){
> -        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
> -              );
> -    }
> +#define YUV2YUVX_FUNC(opt, step)  \
> +void ff_yuv2yuvX_ ##opt(const int16_t *filter, long filterSize, const
> int16_t **src, \
> +                           uint8_t *dest, int dstW, \
> +                           const uint8_t *dither, int offset); \
> +static void yuv2yuvX_ ##opt(const int16_t *filter, int filterSize, \
> +                           const int16_t **src, uint8_t *dest, int dstW, \
> +                           const uint8_t *dither, int offset) \
> +{ \
> +    int remainder = (dstW % step); \
> +    int pixelsProcessed = dstW - remainder; \
> +    if(((uintptr_t)dest) & 15){ \
> +        yuv2yuvX_mmx(filter, filterSize, src, dest, dstW, dither,
> offset); \
> +        return; \
> +    } \
> +    ff_yuv2yuvX_ ##opt(filter, filterSize - 1, src, dest - offset,
> pixelsProcessed + offset, dither, offset); \
> +    if(remainder > 0){ \
> +      yuv2yuvX_mmx(filter, filterSize, src, dest + pixelsProcessed,
> remainder, dither, offset + pixelsProcessed); \
> +    } \
> +    return; \
>  }
> +
> +YUV2YUVX_FUNC(sse3, 32)
> +YUV2YUVX_FUNC(avx2, 64)
> +
>  #endif
>
>  #endif /* HAVE_INLINE_ASM */
> @@ -402,9 +351,14 @@ av_cold void ff_sws_init_swscale_x86(SwsContext *c)
>  #if HAVE_MMXEXT_INLINE
>      if (INLINE_MMXEXT(cpu_flags))
>          sws_init_swscale_mmxext(c);
> -    if (cpu_flags & AV_CPU_FLAG_SSE3){
> -        if(c->use_mmx_vfilter && !(c->flags & SWS_ACCURATE_RND))
> +    if (cpu_flags & AV_CPU_FLAG_AVX2){
> +        if(c->use_mmx_vfilter && !(c->flags & SWS_ACCURATE_RND)){
> +            c->yuv2planeX = yuv2yuvX_avx2;
> +        }
> +    } else if (cpu_flags & AV_CPU_FLAG_SSE3){
> +        if(c->use_mmx_vfilter && !(c->flags & SWS_ACCURATE_RND)){
>              c->yuv2planeX = yuv2yuvX_sse3;
> +        }
>      }
>  #endif
>
> diff --git a/libswscale/x86/yuv2yuvX.asm b/libswscale/x86/yuv2yuvX.asm
> new file mode 100644
> index 0000000000..899b84c50b
> --- /dev/null
> +++ b/libswscale/x86/yuv2yuvX.asm
> @@ -0,0 +1,117 @@
>
> +;******************************************************************************
> +;* x86-optimized yuv2yuvX
> +;* Copyright 2020 Google LLC
> +;* Copyright (C) 2001-2011 Michael Niedermayer <michaelni at gmx.at>
> +;*
> +;* 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, 7, 7, 8, filter, filterSize, src, dest, dstW, dither,
> offset
> +%if ARCH_X86_64
> +    movsxd               dstWq, dstWd
> +    movsxd               offsetq, offsetd
> +%endif ; x86-64
> +    movddup              m0, [filterq + 8]
> +%if cpuflag(avx2)
> +    vpbroadcastq         m3, [ditherq]
> +%else
> +    movq                 xmm3, [ditherq]
> +%endif ; avx2
> +    cmp                  offsetd, 0
> +    jz                   .offset
> +
> +    ; offset != 0 path.
> +    psrlq                m5, m3, $18
> +    psllq                m3, m3, $28
> +    por                  m3, m3, m5
> +
> +.offset:
> +    movd                 xmm1, filterSized
> +%if cpuflag(avx2)
> +    vpbroadcastw         m1, xmm1
> +%else
> +    pshuflw              m1, m1, q0000
> +    punpcklqdq           m1, m1
> +%endif ; avx2
> +    pxor                 m0, m0, m0
> +    mov                  filterSizeq, filterq
> +    mov                  srcq, [filterSizeq]
> +    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:
> +%if cpuflag(avx2)
> +    vpbroadcastq         m0, [filterSizeq + 8]
> +%else
> +    movddup              m0, [filterSizeq + 8]
> +%endif
> +    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                  filterSizeq, $10
> +    mov                  srcq, [filterSizeq]
> +    test                 srcq, srcq
> +    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]
> +%if cpuflag(avx2)
> +    vpermq               m3, m3, 216
> +    vpermq               m6, m6, 216
> +%endif
> +    mova                 [destq + offsetq], m3
> +    mova                 [destq + offsetq + mmsize], m6
> +    add                  offsetq, mmsize * 2
> +    mov                  filterSizeq, filterq
> +    cmp                  offsetq, dstWq
> +    jb                  .outerloop
> +    REP_RET
> +%endmacro
> +
> +INIT_XMM sse3
> +YUV2YUVX_FUNC
> +INIT_YMM avx2
> +YUV2YUVX_FUNC
> diff --git a/tests/checkasm/sw_scale.c b/tests/checkasm/sw_scale.c
> index 9efa2b4def..3bc6066f35 100644
> --- a/tests/checkasm/sw_scale.c
> +++ b/tests/checkasm/sw_scale.c
> @@ -37,6 +37,102 @@
>
>  #define SRC_PIXELS 128
>
> +
> +// This reference function is the same approximate algorithm employed by
> the
> +// SIMD functions
> +static void ref_function(const int16_t *filter, int filterSize,
> +                                                 const int16_t **src,
> uint8_t *dest, int dstW,
> +                                                 const uint8_t *dither,
> int offset)
> +{
> +    int i, d;
> +    d = ((filterSize - 1) * 8 + dither[0]) >> 4;
> +    for (i=0; i<dstW; i++) {
> +        int16_t val = d;
> +        int j;
> +        union {
> +            int val;
> +            int16_t v[2];
> +        } t;
> +        for (j=0; j<filterSize; j++){
> +            t.val = (int)src[j][i + offset] * (int)filter[j];
> +            val += t.v[1];
> +        }
> +        dest[i]= av_clip_uint8(val>>3);
> +    }
> +}
> +
> +static void check_yuv2yuvX(void)
> +{
> +    struct SwsContext *ctx;
> +    int fsi, osi, i, j;
> +#define LARGEST_FILTER 16
> +#define FILTER_SIZES 4
> +    static const int filter_sizes[FILTER_SIZES] = {1, 4, 8, 16};
> +
> +    declare_func_emms(AV_CPU_FLAG_MMX, void, const int16_t *filter,
> +                      int filterSize, const int16_t **src, uint8_t *dest,
> +                      int dstW, const uint8_t *dither, int offset);
> +
> +    int dstW = SRC_PIXELS;
> +    const int16_t **src;
> +    LOCAL_ALIGNED_32(int16_t, src_pixels, [LARGEST_FILTER * SRC_PIXELS]);
> +    LOCAL_ALIGNED_32(int16_t, filter_coeff, [LARGEST_FILTER]);
> +    LOCAL_ALIGNED_32(uint8_t, dst0, [SRC_PIXELS]);
> +    LOCAL_ALIGNED_32(uint8_t, dst1, [SRC_PIXELS]);
> +    LOCAL_ALIGNED_32(uint8_t, dither, [SRC_PIXELS]);
> +    union VFilterData{
> +        const int16_t *src;
> +        uint16_t coeff[8];
> +    } *vFilterData;
> +    uint8_t d_val = rnd();
> +    randomize_buffers(filter_coeff, LARGEST_FILTER);
> +    randomize_buffers(src_pixels, LARGEST_FILTER * SRC_PIXELS);
> +    ctx = sws_alloc_context();
> +    if (sws_init_context(ctx, NULL, NULL) < 0)
> +        fail();
> +
> +    ff_getSwsFunc(ctx);
> +    for(i = 0; i < SRC_PIXELS; ++i){
> +        dither[i] = d_val;
> +    }
> +    for(osi = 0; osi < 64; osi += 16){
> +        for(fsi = 0; fsi < FILTER_SIZES; ++fsi){
> +            src = av_malloc(sizeof(int16_t*) * filter_sizes[fsi]);
> +            vFilterData = av_malloc((filter_sizes[fsi] + 2) *
> sizeof(union VFilterData));
> +            memset(vFilterData, 0, (filter_sizes[fsi] + 2) * sizeof(union
> VFilterData));
> +            for(i = 0; i < filter_sizes[fsi]; ++i){
> +                src[i] = &src_pixels[i * SRC_PIXELS];
> +                vFilterData[i].src = src[i];
> +                for(j = 0; j < 4; ++j){
> +                    vFilterData[i].coeff[j + 4] = filter_coeff[i];
> +                }
> +            }
> +            if (check_func(ctx->yuv2planeX, "yuv2yuvX_%d_%d",
> filter_sizes[fsi], osi)){
> +                memset(dst0, 0, SRC_PIXELS * sizeof(dst0[0]));
> +                memset(dst1, 0, SRC_PIXELS * sizeof(dst1[0]));
> +
> +                // The reference function is not the scalar function
> selected when mmx
> +                // is deactivated as the SIMD functions do not give the
> same result as
> +                // the scalar ones due to rounding. The SIMD functions
> are activated by
> +                // the flag SWS_ACCURATE_RND
> +                ref_function(&filter_coeff[0], filter_sizes[fsi], src,
> dst0, dstW - osi, dither, osi);
> +                // There's no point in calling new for the reference
> function
> +                if(ctx->use_mmx_vfilter){
> +                    call_new((const int16_t*)vFilterData,
> filter_sizes[fsi], src, dst1, dstW - osi, dither, osi);
> +                    if (memcmp(dst0, dst1, SRC_PIXELS * sizeof(dst0[0]))){
> +                        fail();
> +                    }
> +                    bench_new((const int16_t*)vFilterData,
> filter_sizes[fsi], src, dst1, dstW - osi, dither, osi);
> +                }
> +            }
> +            free(src);
> +            free(vFilterData);
> +        }
> +    }
> +    sws_freeContext(ctx);
> +#undef FILTER_SIZES
> +}
> +
>  static void check_hscale(void)
>  {
>  #define MAX_FILTER_WIDTH 40
> @@ -131,4 +227,6 @@ void checkasm_check_sw_scale(void)
>  {
>      check_hscale();
>      report("hscale");
> +    check_yuv2yuvX();
> +    report("yuv2yuvX");
>  }
> --
> 2.29.2.684.gfbc64c5ab5-goog
>
>


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