[Mesa-dev] [PATCH RFC] mesa: add SSE optimisation for glDrawElements
Timothy Arceri
t_arceri at yahoo.com.au
Fri Oct 24 05:28:59 PDT 2014
On Thu, 2014-10-23 at 09:20 -0600, Brian Paul wrote:
> Nice, just a few comments below.
>
>
> On 10/22/2014 10:02 PM, 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/Makefile.am | 3 +-
> > src/mesa/main/sse_minmax.c | 75 +++++++++++++++++++++++++++++++++++++++++++
> > src/mesa/main/sse_minmax.h | 29 +++++++++++++++++
> > src/mesa/vbo/vbo_exec_array.c | 8 +++++
> > 4 files changed, 114 insertions(+), 1 deletion(-)
> > create mode 100644 src/mesa/main/sse_minmax.c
> > create mode 100644 src/mesa/main/sse_minmax.h
> >
> > I almost wasn't going to bother sending this out since it uses SSE4.1
> > and its recommended to use glDrawRangeElements anyway. But since these games
> > are still ofter used for benchmarking I thought I'd see if anyone is
> > interested in this. I only optimised GL_UNSIGNED_INT as that was the
> > only place these games were hitting but I guess it wouldn't hurt
> > to optimse the other cases too.
> >
> > I think it would probably make sense too to just combine
> > streaming-load-memcpy.c and sse_minmax.c into a single file
> > something like sse_opt.c for example.
> >
> > As far a frame rates go I couldn't see any concrete improments
> > on my Ivybridge machine. Maybe it would help more on a high end radeon
> > card where cpu apparently is more of a concern??
> >
> > Finally its seems to run fine but its only the second time I've tried
> > these type of optimisations so let me know if there are any obvious
> > mistakes or improvements.
> >
> > 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
>
> I think you also need to add the new file to Makefile.sources for SCons
> (also check Android).
>
> Alternately, since the function is pretty small, and I'm not sure if it
> would be used elsewhere, you might put it in the vbo_exec_array.c file.
Correct me if I'm wrong but I don't think I can do this or the compiler
might end up generating SSE4.1 instructions for the other functions in
vbo_exec_array.c the same would apply with your later suggestion for
moving the c code into the sse_minmax.c file.
>
>
> > diff --git a/src/mesa/main/sse_minmax.c b/src/mesa/main/sse_minmax.c
> > new file mode 100644
> > index 0000000..1625407
> > --- /dev/null
> > +++ b/src/mesa/main/sse_minmax.c
> > @@ -0,0 +1,75 @@
> > +/*
> > + * 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/glheader.h"
> > +#include "main/sse_minmax.h"
> > +#include <smmintrin.h>
> > +
> > +void
> > +sse_minmax(const GLuint *ui_indices, GLuint *min_index, GLuint *max_index, const GLuint count)
>
> We normally prefix non-static functions with _mesa_.
>
>
> > +{
> > + GLuint i = 0;
> > + GLuint max_ui = 0;
> > + GLuint min_ui = ~0U;
> > + GLuint max_arr[4] = {0};
> > + GLuint min_arr[4] = {0};
>
> Do those two vars really need to be initialized?
>
>
> > + GLuint vec_count;
> > + __m128i max_ui4 = _mm_setzero_si128();
> > + __m128i min_ui4 = _mm_set1_epi32(~0U);
> > + __m128i ui_indices4;
> > + __m128i *ui_indices_ptr;
>
> Some of those declarations could be moved inside the if statement.
>
> > +
> > + if (count >= 4) {
> > + vec_count = count - (count % 4);
> > + ui_indices_ptr = (__m128i*)ui_indices;
> > + for (i = 0; i < vec_count/4; i++) {
> > + ui_indices4 = _mm_loadu_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_ps((float*)max_arr, _mm_castsi128_ps(max_ui4));
> > + _mm_store_ps((float*)min_arr, _mm_castsi128_ps(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];
>
> Let's put the condition and the assignment on separate lines (I know
> it's like this in the original code).
>
>
> > + }
> > + i = vec_count;
> > + }
> > +
> > + for (; 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;
> > +}
>
>
> BTW, another way to structure this would be something like this:
>
> void
> _mesa_uint_array_min_max(const GLuint *ui_indices, GLuint *min_index,
> GLuint *max_index, GLuint count)
> {
> #ifdef __SSE4_1__
> // sse code
> #else
> // C code
> #endif
> }
>
> Then you could get rid of the #ifdef __SSE4_1__ at the call site.
>
> Also, it would be easy to implement debug/cross-check code in the
> function where the C code would verify the result of the SSE code to
> make sure it's correct.
>
> Not a big deal though.
>
> Can something similar be done for 16-bit values?
>
> -Brian
>
>
> > +
> > +#endif
> > diff --git a/src/mesa/main/sse_minmax.h b/src/mesa/main/sse_minmax.h
> > new file mode 100644
> > index 0000000..d14db26
> > --- /dev/null
> > +++ b/src/mesa/main/sse_minmax.h
> > @@ -0,0 +1,29 @@
> > +/*
> > + * 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.
> > + *
> > + * Authors:
> > + * Timothy Arceri <t_arceri at yahoo.com.au>
> > + *
> > + */
> > +
> > +void
> > +sse_minmax(const GLuint *ui_indices, GLuint *min_index, GLuint *max_index, const GLuint count);
> > diff --git a/src/mesa/vbo/vbo_exec_array.c b/src/mesa/vbo/vbo_exec_array.c
> > index 045dbb5..0399348 100644
> > --- a/src/mesa/vbo/vbo_exec_array.c
> > +++ b/src/mesa/vbo/vbo_exec_array.c
> > @@ -36,6 +36,9 @@
> > #include "main/enums.h"
> > #include "main/macros.h"
> > #include "main/transformfeedback.h"
> > +#ifdef __SSE4_1__
> > +#include "main/sse_minmax.h"
> > +#endif
> >
> > #include "vbo_context.h"
> >
> > @@ -110,6 +113,7 @@ vbo_get_minmax_index(struct gl_context *ctx,
> > const GLuint *ui_indices = (const GLuint *)indices;
> > GLuint max_ui = 0;
> > GLuint min_ui = ~0U;
> > +
> > if (restart) {
> > for (i = 0; i < count; i++) {
> > if (ui_indices[i] != restartIndex) {
> > @@ -119,10 +123,14 @@ vbo_get_minmax_index(struct gl_context *ctx,
> > }
> > }
> > else {
> > +#ifdef __SSE4_1__
> > + sse_minmax(ui_indices, &min_ui, &max_ui, count);
> > +#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];
> > }
> > +#endif
> > }
> > *min_index = min_ui;
> > *max_index = max_ui;
> >
>
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