[Mesa-dev] [PATCH 2/5] i965/tiled_memcpy: inline movntdqa loads in tiled_to_linear
Chris Wilson
chris at chris-wilson.co.uk
Thu Apr 5 19:57:30 UTC 2018
Quoting Chris Wilson (2018-04-05 20:54:54)
> Quoting Scott D Phillips (2018-04-03 21:05:42)
> > The reference for MOVNTDQA says:
> >
> > For WC memory type, the nontemporal hint may be implemented by
> > loading a temporary internal buffer with the equivalent of an
> > aligned cache line without filling this data to the cache.
> > [...] Subsequent MOVNTDQA reads to unread portions of the WC
> > cache line will receive data from the temporary internal
> > buffer if data is available.
> >
> > This hidden cache line sized temporary buffer can improve the
> > read performance from wc maps.
> > ---
> > src/mesa/drivers/dri/i965/Makefile.am | 7 ++++
> > src/mesa/drivers/dri/i965/Makefile.sources | 6 ++-
> > src/mesa/drivers/dri/i965/intel_tiled_memcpy.c | 52 ++++++++++++++++++++++++++
> > src/mesa/drivers/dri/i965/meson.build | 18 +++++++--
> > 4 files changed, 78 insertions(+), 5 deletions(-)
> >
> > diff --git a/src/mesa/drivers/dri/i965/Makefile.am b/src/mesa/drivers/dri/i965/Makefile.am
> > index 889d4c68a2b..ff47add93f4 100644
> > --- a/src/mesa/drivers/dri/i965/Makefile.am
> > +++ b/src/mesa/drivers/dri/i965/Makefile.am
> > @@ -92,8 +92,14 @@ libi965_gen11_la_CFLAGS = $(AM_CFLAGS) -DGEN_VERSIONx10=110
> >
> > noinst_LTLIBRARIES = \
> > libi965_dri.la \
> > + libintel_tiled_memcpy.la \
> > $(I965_PERGEN_LIBS)
> >
> > +libintel_tiled_memcpy_la_SOURCES = \
> > + $(intel_tiled_memcpy_FILES)
> > +libintel_tiled_memcpy_la_CFLAGS = \
> > + $(AM_CFLAGS) $(SSE41_CFLAGS)
> > +
> > libi965_dri_la_SOURCES = \
> > $(i965_FILES) \
> > $(i965_oa_GENERATED_FILES)
> > @@ -104,6 +110,7 @@ libi965_dri_la_LIBADD = \
> > $(top_builddir)/src/intel/compiler/libintel_compiler.la \
> > $(top_builddir)/src/intel/blorp/libblorp.la \
> > $(I965_PERGEN_LIBS) \
> > + libintel_tiled_memcpy.la
> > $(LIBDRM_LIBS)
>
> Makes sense.
>
> > diff --git a/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c b/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c
> > index 7c6bde990d6..d076351b322 100644
> > --- a/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c
> > +++ b/src/mesa/drivers/dri/i965/intel_tiled_memcpy.c
> > @@ -36,6 +36,10 @@
> > #include "brw_context.h"
> > #include "intel_tiled_memcpy.h"
> >
> > +#if defined(USE_SSE41)
> > +#include "main/streaming-load-memcpy.h"
> > +#include <smmintrin.h>
> > +#endif
> > #if defined(__SSSE3__)
> > #include <tmmintrin.h>
> > #elif defined(__SSE2__)
> > @@ -213,6 +217,30 @@ rgba8_copy_aligned_src(void *dst, const void *src, size_t bytes)
> > return dst;
> > }
> >
> > +#if defined(USE_SSE41)
> > +static ALWAYS_INLINE void*
>
> Space in that void*? (but don't quote me on mesa/i965 preferred style!)
>
> > +_memcpy_streaming_load(void *dest, const void *src, size_t count)
> > +{
> > + if (count == 16) {
> > + __m128i val = _mm_stream_load_si128((__m128i *)src);
> > + _mm_store_si128((__m128i *)dest, val);
> > + return dest;
> > + } else if (count == 64) {
> > + __m128i val0 = _mm_stream_load_si128(((__m128i *)src) + 0);
> > + __m128i val1 = _mm_stream_load_si128(((__m128i *)src) + 1);
> > + __m128i val2 = _mm_stream_load_si128(((__m128i *)src) + 2);
> > + __m128i val3 = _mm_stream_load_si128(((__m128i *)src) + 3);
> > + _mm_store_si128(((__m128i *)dest) + 0, val0);
> > + _mm_store_si128(((__m128i *)dest) + 1, val1);
> > + _mm_store_si128(((__m128i *)dest) + 2, val2);
> > + _mm_store_si128(((__m128i *)dest) + 3, val3);
> > + return dest;
> > + } else {
>
> assert(count < 16); or assert(count < 64) ?
>
> Might as well remind the reader (and caller?!) that this is only for
> copying the residuals.
>
> > + return memcpy(dest, src, count);
> > + }
> > +}
> > +#endif
> > +
> > /**
> > * Each row from y0 to y1 is copied in three parts: [x0,x1), [x1,x2), [x2,x3).
> > * These ranges are in bytes, i.e. pixels * bytes-per-pixel.
> > @@ -677,6 +705,12 @@ xtiled_to_linear_faster(uint32_t x0, uint32_t x1, uint32_t x2, uint32_t x3,
> > return xtiled_to_linear(0, 0, xtile_width, xtile_width, 0, xtile_height,
> > dst, src, dst_pitch, swizzle_bit,
> > rgba8_copy, rgba8_copy_aligned_src);
> > +#if defined(USE_SSE41)
> > + else if (mem_copy == (mem_copy_fn)_mesa_streaming_load_memcpy)
> > + return xtiled_to_linear(0, 0, xtile_width, xtile_width, 0, xtile_height,
> > + dst, src, dst_pitch, swizzle_bit, memcpy,
> > + _memcpy_streaming_load);
>
> Please group memcpy and _memcpy_streaming_load (put the line brea before
> to keep them on the same line).
>
> > +#endif
> > else
> > unreachable("not reached");
> > } else {
> > @@ -687,6 +721,12 @@ xtiled_to_linear_faster(uint32_t x0, uint32_t x1, uint32_t x2, uint32_t x3,
> > return xtiled_to_linear(x0, x1, x2, x3, y0, y1,
> > dst, src, dst_pitch, swizzle_bit,
> > rgba8_copy, rgba8_copy_aligned_src);
> > +#if defined(USE_SSE41)
> > + else if (mem_copy == (mem_copy_fn)_mesa_streaming_load_memcpy)
> > + return xtiled_to_linear(x0, x1, x2, x3, y0, y1,
> > + dst, src, dst_pitch, swizzle_bit, memcpy,
> > + _memcpy_streaming_load);
> > +#endif
> > else
> > unreachable("not reached");
> > }
> > @@ -719,6 +759,12 @@ ytiled_to_linear_faster(uint32_t x0, uint32_t x1, uint32_t x2, uint32_t x3,
> > return ytiled_to_linear(0, 0, ytile_width, ytile_width, 0, ytile_height,
> > dst, src, dst_pitch, swizzle_bit,
> > rgba8_copy, rgba8_copy_aligned_src);
> > +#if defined(USE_SSE41)
> > + else if (mem_copy == (mem_copy_fn)_mesa_streaming_load_memcpy)
> > + return ytiled_to_linear(0, 0, ytile_width, ytile_width, 0, ytile_height,
> > + dst, src, dst_pitch, swizzle_bit,
> > + memcpy, _memcpy_streaming_load);
> > +#endif
> > else
> > unreachable("not reached");
> > } else {
> > @@ -729,6 +775,12 @@ ytiled_to_linear_faster(uint32_t x0, uint32_t x1, uint32_t x2, uint32_t x3,
> > return ytiled_to_linear(x0, x1, x2, x3, y0, y1,
> > dst, src, dst_pitch, swizzle_bit,
> > rgba8_copy, rgba8_copy_aligned_src);
> > +#if defined(USE_SSE41)
> > + else if (mem_copy == (mem_copy_fn)_mesa_streaming_load_memcpy)
> > + return ytiled_to_linear(x0, x1, x2, x3, y0, y1,
> > + dst, src, dst_pitch, swizzle_bit,
> > + memcpy, _memcpy_streaming_load);
> > +#endif
> > else
> > unreachable("not reached");
> > }
>
> Ok, was hoping to see how you choose to use the streaming load, but I
> guess that's the next patch.
>
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
Oh, one point Eric Anholt mentioned on another thread about movntqda is
that stale data inside the internal buffer is not automatically
invalidated. We may need to emit explicit mfence before the copies if we
are in doubt. A single mfence per tiled-copy is probably not enough to
worry about optimising away.
-Chris
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