[Mesa-dev] [PATCH 2/3] mesa/main: Add sse2 streaming clamping

Bruno Jimenez brunojimen at gmail.com
Thu Nov 13 13:45:43 PST 2014


On Wed, 2014-11-12 at 21:47 +0200, Juha-Pekka Heikkila wrote:
> On 12.11.2014 19:36, Bruno Jimenez wrote:
> > On Wed, 2014-11-12 at 14:50 +0200, Juha-Pekka Heikkila wrote:
> >> Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila at gmail.com>
> >> ---
> >>  src/mesa/Makefile.am          |   8 +++
> >>  src/mesa/main/sse2_clamping.c | 138 ++++++++++++++++++++++++++++++++++++++++++
> >>  src/mesa/main/sse2_clamping.h |  49 +++++++++++++++
> >>  3 files changed, 195 insertions(+)
> >>  create mode 100644 src/mesa/main/sse2_clamping.c
> >>  create mode 100644 src/mesa/main/sse2_clamping.h
> >>
> >> diff --git a/src/mesa/Makefile.am b/src/mesa/Makefile.am
> >> index 932db4f..43dbe87 100644
> >> --- a/src/mesa/Makefile.am
> >> +++ b/src/mesa/Makefile.am
> >> @@ -111,6 +111,10 @@ if SSE41_SUPPORTED
> >>  ARCH_LIBS += libmesa_sse41.la
> >>  endif
> >>  
> >> +if SSE2_SUPPORTED
> >> +ARCH_LIBS += libmesa_sse2.la
> >> +endif
> >> +
> >>  MESA_ASM_FILES_FOR_ARCH =
> >>  
> >>  if HAVE_X86_ASM
> >> @@ -155,6 +159,10 @@ libmesa_sse41_la_SOURCES = \
> >>  	main/sse_minmax.c
> >>  libmesa_sse41_la_CFLAGS = $(AM_CFLAGS) -msse4.1
> >>  
> >> +libmesa_sse2_la_SOURCES = \
> >> +	main/sse2_clamping.c
> >> +libmesa_sse2_la_CFLAGS = $(AM_CFLAGS) -msse2
> >> +
> >>  pkgconfigdir = $(libdir)/pkgconfig
> >>  pkgconfig_DATA = gl.pc
> >>  
> >> diff --git a/src/mesa/main/sse2_clamping.c b/src/mesa/main/sse2_clamping.c
> >> new file mode 100644
> >> index 0000000..66c7dc7
> >> --- /dev/null
> >> +++ b/src/mesa/main/sse2_clamping.c
> >> @@ -0,0 +1,138 @@
> >> +/*
> >> + * Copyright © 2014 Intel Corporation
> >> + *
> >> + * Permission is hereby granted, free of charge, to any person obtaining a
> >> + * copy of this software and associated documentation files (the "Software"),
> >> + * to deal in the Software without restriction, including without limitation
> >> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> >> + * and/or sell copies of the Software, and to permit persons to whom the
> >> + * Software is furnished to do so, subject to the following conditions:
> >> + *
> >> + * The above copyright notice and this permission notice (including the next
> >> + * paragraph) shall be included in all copies or substantial portions of the
> >> + * Software.
> >> + *
> >> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> >> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> >> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> >> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> >> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> >> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> >> + * IN THE SOFTWARE.
> >> + *
> >> + * Authors:
> >> + *    Juha-Pekka Heikkila <juhapekka.heikkila at gmail.com>
> >> + *
> >> + */
> >> +
> >> +#ifdef __SSE2__
> >> +#include "main/macros.h"
> >> +#include "main/sse2_clamping.h"
> >> +#include <emmintrin.h>
> >> +
> >> +/**
> >> + * Clamp four float values to [min,max]
> >> + */
> >> +static inline void
> >> +_mesa_clamp_float_rgba(GLfloat src[4], GLfloat result[4], const float min,
> >> +                       const float max)
> >> +{
> >> +   __m128  operand, minval, maxval;
> >> +
> >> +   operand = _mm_loadu_ps(src);
> >> +   minval = _mm_set1_ps(min);
> >> +   maxval = _mm_set1_ps(max);
> >> +   operand = _mm_max_ps(operand, minval);
> >> +   operand = _mm_min_ps(operand, maxval);
> >> +   _mm_storeu_ps(result, operand);
> >> +}
> >> +
> >> +
> >> +/* Clamp n amount float rgba pixels to [min,max] using SSE2
> >> + */
> >> +__attribute__((optimize("unroll-loops")))
> >> +void
> >> +_mesa_streaming_clamp_float_rgba(const GLuint n, GLfloat rgba_src[][4],
> >> +                                 GLfloat rgba_dst[][4], const GLfloat min,
> >> +                                 const GLfloat max)
> >> +{
> >> +   int      c, prefetch_c;
> >> +   float*   worker = &rgba_src[0][0];
> >> +   __m128   operand[2], minval, maxval;
> >> +
> >> +   _mm_prefetch((char*) (((unsigned long)worker)|0x1f) + 65, _MM_HINT_T0);
> >                                                    ^^^^    ^^^
> > 
> > Hi,
> > 
> > May I ask why precisely this numbers?
> 
> 0x1f as you note below is a typo, should be 0x0f. 65 is cache line
> length added with one to even the |0x1f operation.

Hi,

I supposed that it could be something like that, but I wasn't fully
sure, thanks for the answer.

> 
> > 
> >> +
> >> +   minval = _mm_set1_ps(min);
> >> +   maxval = _mm_set1_ps(max);
> >> +
> >> +   for (c = n*4; c > 0 && (((unsigned long)worker)&0x1f) != 0; c--, worker++) {
> >                                                     ^^^^^
> > 
> > I guess that this is for alignment, but you only need to align to a 16
> > bytes boundary, not 32. Or maybe I am missing something obvious.
> > 
> 
> You are correct, 0x1f is typo. should be 0x0f
> 
> >> +      operand[0] = _mm_load_ss(worker);
> >> +      operand[0] = _mm_max_ss(operand[0], minval);
> >> +      operand[0] = _mm_min_ss(operand[0], maxval);
> >> +      _mm_store_ss(worker, operand[0]);
> >> +   }
> >> +
> >> +   while (c >= 8) {
> >> +      _mm_prefetch((char*) worker + 64, _MM_HINT_T0);
> >                                       ^^^
> >> +
> >> +      for (prefetch_c = 64/8; prefetch_c > 0 && c >= 8; prefetch_c--, c-=8,
> >                           ^^^^
> > 
> > May I ask also why this numbers?
> > 
> 
> 64 is cache line length in bytes, 8 mean this loop handle 8 floats in
> one go, operand[0] get 4 floats and same goes for operand[1]. I found
> interleaving this way to give more performance, adding more operands did
> not give any more performance thus 2 operands to work with which turn
> into the number 8. Now that you asked I think 64 has to be divided by 32
> and not 8 (8 elements, each 4 bytes -> 32)
> 
> Idea here is we send prefetch for next cache line before we start to
> work with current line, arriving to next loop iteration we already have
> new cache line ready.

I guess that, as the access is serial, the CPU might be able to predict
that it will need the next block of data.

Thanks a lot :)
Bruno

> 
> > 
> >> +           worker += 8) {
> >> +
> >> +         operand[0] = _mm_load_ps(worker);
> >> +         operand[1] = _mm_load_ps(worker+4);
> >> +         operand[0] = _mm_max_ps(operand[0], minval);
> >> +         operand[1] = _mm_max_ps(operand[1], minval);
> >> +         operand[0] = _mm_min_ps(operand[0], maxval);
> >> +         operand[1] = _mm_min_ps(operand[1], maxval);
> >> +
> >> +         _mm_store_ps(worker, operand[0]);
> >> +         _mm_store_ps(worker+4, operand[1]);
> >> +      }
> >> +   }
> >> +
> >> +   for (; c > 0; c--, worker++) {
> >> +      operand[0] = _mm_load_ss(worker);
> >> +      operand[0] = _mm_max_ss(operand[0], minval);
> >> +      operand[0] = _mm_min_ss(operand[0], maxval);
> >> +      _mm_store_ss(worker, operand[0]);
> >> +   }
> >> +}
> >> +
> >> +
> >> +/* Clamp n amount float rgba pixels to [min,max] using SSE2 and apply
> >> + * scaling and mapping to components.
> >> + *
> >> + * this replace handling of [RGBA] channels:
> >> + * rgba_temp[RCOMP] = CLAMP(rgba[i][RCOMP], 0.0F, 1.0F);
> >> + * rgba[i][RCOMP] = rMap[F_TO_I(rgba_temp[RCOMP] * scale[RCOMP])];
> >> + */
> >> +void
> >> +_mesa_clamp_float_rgba_scale_and_map(const GLuint n, GLfloat rgba_src[][4],
> >> +                                     GLfloat rgba_dst[][4], const GLfloat min,
> >> +                                     const GLfloat max,
> >> +                                     const GLfloat scale[4],
> >> +                                     const GLfloat* rMap, const GLfloat* gMap,
> >> +                                     const GLfloat* bMap, const GLfloat* aMap)
> >> +{
> >> +   int i;
> >> +   GLfloat __attribute__((aligned(16))) temp[4];
> >> +   __m128  *operand = (__m128*) &temp, multiplier, mmove;
> >> +   __m128i truncated_integers;
> >> +
> >> +   const unsigned int* map_p = (const unsigned int*) &truncated_integers;
> >> +
> >> +   multiplier = _mm_loadu_ps(scale);
> >> +
> >> +   for(i = 0; i < n; i++) {
> >> +      _mesa_clamp_float_rgba(rgba_src[i], temp, min, max);
> >> +
> >> +      *operand = _mm_mul_ps(multiplier, *operand);
> >> +      truncated_integers = _mm_cvttps_epi32(*operand);
> >> +      mmove = _mm_set_ps(aMap[map_p[ACOMP]], bMap[map_p[BCOMP]],
> >> +                         gMap[map_p[GCOMP]], rMap[map_p[RCOMP]] );
> >> +
> >> +      _mm_storeu_ps(rgba_dst[i], mmove);
> >> +   }
> >> +}
> >> +
> >> +#endif /* __SSE2__ */
> >> diff --git a/src/mesa/main/sse2_clamping.h b/src/mesa/main/sse2_clamping.h
> >> new file mode 100644
> >> index 0000000..688fab7
> >> --- /dev/null
> >> +++ b/src/mesa/main/sse2_clamping.h
> >> @@ -0,0 +1,49 @@
> >> +/*
> >> + * Copyright © 2014 Intel Corporation
> >> + *
> >> + * Permission is hereby granted, free of charge, to any person obtaining a
> >> + * copy of this software and associated documentation files (the "Software"),
> >> + * to deal in the Software without restriction, including without limitation
> >> + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> >> + * and/or sell copies of the Software, and to permit persons to whom the
> >> + * Software is furnished to do so, subject to the following conditions:
> >> + *
> >> + * The above copyright notice and this permission notice (including the next
> >> + * paragraph) shall be included in all copies or substantial portions of the
> >> + * Software.
> >> + *
> >> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> >> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> >> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> >> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> >> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> >> + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> >> + * IN THE SOFTWARE.
> >> + *
> >> + * Authors:
> >> + *    Juha-Pekka Heikkila <juhapekka.heikkila at gmail.com>
> >> + *
> >> + */
> >> +
> >> +#ifdef __SSE2__
> >> +
> >> +/* Clamp n amount float rgba pixels to [min,max] using SSE2
> >> + */
> >> +void
> >> +_mesa_streaming_clamp_float_rgba(const GLuint n, GLfloat rgba_src[][4],
> >> +                                 GLfloat rgba_dst[][4], const GLfloat min,
> >> +                                 const GLfloat max);
> >> +
> >> +
> >> +/* Clamp n amount float rgba pixels to [min,max] using SSE2 and apply
> >> + * scaling and mapping to components.
> >> + */
> >> +void
> >> +_mesa_clamp_float_rgba_scale_and_map(const GLuint n, GLfloat rgba_src[][4],
> >> +                                     GLfloat rgba_dst[][4], const GLfloat min,
> >> +                                     const GLfloat max,
> >> +                                     const GLfloat scale[4],
> >> +                                     const GLfloat* rMap, const GLfloat* gMap,
> >> +                                     const GLfloat* bMap, const GLfloat* aMap);
> >> +
> >> +#endif /* __SSE2__ */
> > 
> > 
> 




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