[Mesa-dev] [PATCH V4] mesa: add SSE optimisation for glDrawElements

Bruno Jimenez brunojimen at gmail.com
Mon Oct 27 08:04:04 PDT 2014


On Mon, 2014-10-27 at 08:37 +1100, Timothy Arceri wrote:
> Makes use of SSE to speed up compute of min and max elements
> 
> Callgrind cpu usage results from pts benchmarks:
> 
> Openarena 0.8.8: 3.67% -> 1.03%
> UrbanTerror: 2.36% -> 0.81%
> 
> Signed-off-by: Timothy Arceri <t_arceri at yahoo.com.au>
> ---
>  src/mesa/Android.libmesa_dricore.mk |  3 +-
>  src/mesa/Makefile.am                |  3 +-
>  src/mesa/main/sse_minmax.c          | 93 +++++++++++++++++++++++++++++++++++++
>  src/mesa/main/sse_minmax.h          | 30 ++++++++++++
>  src/mesa/vbo/vbo_exec_array.c       | 14 ++++--
>  5 files changed, 138 insertions(+), 5 deletions(-)
>  create mode 100644 src/mesa/main/sse_minmax.c
>  create mode 100644 src/mesa/main/sse_minmax.h
> 
> V4:
> - fixed bugs with incrementing pointer and updating counters
> 
> V3:
> 
> - Removed sse_minmax.c from Makefile.sources
> - handle the first few values without SSE until the pointer is aligned
>  and use _mm_load_si128 rather than _mm_loadu_si128
> - guard the call to the SSE code better at build time
> 
> diff --git a/src/mesa/Android.libmesa_dricore.mk b/src/mesa/Android.libmesa_dricore.mk
> index 1e6d948..52d626f 100644
> --- a/src/mesa/Android.libmesa_dricore.mk
> +++ b/src/mesa/Android.libmesa_dricore.mk
> @@ -51,7 +51,8 @@ endif # MESA_ENABLE_ASM
>  
>  ifeq ($(ARCH_X86_HAVE_SSE4_1),true)
>  LOCAL_SRC_FILES += \
> -	$(SRCDIR)main/streaming-load-memcpy.c
> +	$(SRCDIR)main/streaming-load-memcpy.c \
> +	$(SRCDIR)main/sse_minmax.c
>  LOCAL_CFLAGS := -msse4.1
>  endif
>  
> diff --git a/src/mesa/Makefile.am b/src/mesa/Makefile.am
> index e71bccb..932db4f 100644
> --- a/src/mesa/Makefile.am
> +++ b/src/mesa/Makefile.am
> @@ -151,7 +151,8 @@ libmesagallium_la_LIBADD = \
>  	$(ARCH_LIBS)
>  
>  libmesa_sse41_la_SOURCES = \
> -	main/streaming-load-memcpy.c
> +	main/streaming-load-memcpy.c \
> +	main/sse_minmax.c
>  libmesa_sse41_la_CFLAGS = $(AM_CFLAGS) -msse4.1
>  
>  pkgconfigdir = $(libdir)/pkgconfig
> diff --git a/src/mesa/main/sse_minmax.c b/src/mesa/main/sse_minmax.c
> new file mode 100644
> index 0000000..6bf5fe3
> --- /dev/null
> +++ b/src/mesa/main/sse_minmax.c
> @@ -0,0 +1,93 @@
> +/*
> + * Copyright © 2014 Timothy Arceri
> + *
> + * 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.
> + *
> + * Author:
> + *    Timothy Arceri <t_arceri at yahoo.com.au>
> + *
> + */
> +
> +#ifdef __SSE4_1__
> +#include "main/sse_minmax.h"
> +#include <smmintrin.h>
> +#include <stdint.h>
> +
> +void
> +_mesa_uint_array_min_max(const unsigned *ui_indices, unsigned *min_index,
> +                         unsigned *max_index, const unsigned count)
> +{
> +   unsigned max_ui = 0;
> +   unsigned min_ui = ~0U;
> +   unsigned i = 0;
> +   unsigned aligned_count = count;
> +
> +   /* handle the first few values without SSE until the pointer is aligned */
> +   while (((uintptr_t)ui_indices & 15) && aligned_count) {
> +      if (*ui_indices > max_ui)
> +         max_ui = *ui_indices;
> +      if (*ui_indices < min_ui)
> +         min_ui = *ui_indices;
> +
> +      aligned_count--;
> +      ui_indices++;
> +   }
> +
> +   if (aligned_count >= 4) {
                          ^^

Hi,

I have been thinking and I think that you can change that 4 for an 8. In
the case aligned_count == 4 there's no gain in using SSE, as you will
have to do a final reduction from 4 elements to 1.

- Bruno

> +      unsigned max_arr[4] __attribute__ ((aligned (16)));
> +      unsigned min_arr[4] __attribute__ ((aligned (16)));
> +      unsigned vec_count;
> +      __m128i max_ui4 = _mm_setzero_si128();
> +      __m128i min_ui4 = _mm_set1_epi32(~0U);
> +      __m128i ui_indices4;
> +      __m128i *ui_indices_ptr;
> +
> +      vec_count = aligned_count & ~0x3;
> +      ui_indices_ptr = (__m128i*)ui_indices;
> +      for (i = 0; i < vec_count / 4; i++) {
> +         ui_indices4 = _mm_load_si128(&ui_indices_ptr[i]);
> +         max_ui4 = _mm_max_epu32(ui_indices4, max_ui4);
> +         min_ui4 = _mm_min_epu32(ui_indices4, min_ui4);
> +      }
> +
> +      _mm_store_si128((__m128i*)max_arr, max_ui4);
> +      _mm_store_si128((__m128i*)min_arr, min_ui4);
> +
> +      for (i = 0; i < 4; i++) {
> +         if (max_arr[i] > max_ui)
> +            max_ui = max_arr[i];
> +         if (min_arr[i] < min_ui)
> +            min_ui = min_arr[i];
> +      }
> +      i = vec_count;
> +   }
> +
> +   for (; i < aligned_count; i++) {
> +      if (ui_indices[i] > max_ui)
> +         max_ui = ui_indices[i];
> +      if (ui_indices[i] < min_ui)
> +         min_ui = ui_indices[i];
> +   }
> +
> +   *min_index = min_ui;
> +   *max_index = max_ui;
> +}
> +
> +#endif
> diff --git a/src/mesa/main/sse_minmax.h b/src/mesa/main/sse_minmax.h
> new file mode 100644
> index 0000000..953c4e9
> --- /dev/null
> +++ b/src/mesa/main/sse_minmax.h
> @@ -0,0 +1,30 @@
> +/*
> + * Copyright © 2014 Timothy Arceri
> + *
> + * 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.
> + *
> + * Author:
> + *    Timothy Arceri <t_arceri at yahoo.com.au>
> + *
> + */
> +
> +void
> +_mesa_uint_array_min_max(const unsigned *ui_indices, unsigned *min_index,
> +                         unsigned *max_index, const unsigned count);
> diff --git a/src/mesa/vbo/vbo_exec_array.c b/src/mesa/vbo/vbo_exec_array.c
> index 045dbb5..e623b36 100644
> --- a/src/mesa/vbo/vbo_exec_array.c
> +++ b/src/mesa/vbo/vbo_exec_array.c
> @@ -36,6 +36,8 @@
>  #include "main/enums.h"
>  #include "main/macros.h"
>  #include "main/transformfeedback.h"
> +#include "main/sse_minmax.h"
> +#include "x86/common_x86_asm.h"
>  
>  #include "vbo_context.h"
>  
> @@ -119,10 +121,16 @@ vbo_get_minmax_index(struct gl_context *ctx,
>           }
>        }
>        else {
> -         for (i = 0; i < count; i++) {
> -            if (ui_indices[i] > max_ui) max_ui = ui_indices[i];
> -            if (ui_indices[i] < min_ui) min_ui = ui_indices[i];
> +#if defined(USE_SSE41)
> +         if (cpu_has_sse4_1) {
> +            _mesa_uint_array_min_max(ui_indices, &min_ui, &max_ui, count);
>           }
> +         else
> +#endif
> +            for (i = 0; i < count; i++) {
> +               if (ui_indices[i] > max_ui) max_ui = ui_indices[i];
> +               if (ui_indices[i] < min_ui) min_ui = ui_indices[i];
> +            }
>        }
>        *min_index = min_ui;
>        *max_index = max_ui;




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