[FFmpeg-devel] [FFMpeg-Devel][GSoC][PATCH 1/6] postproc: Replaced inline asm for prefetching with prefetch functions
Tucker DiNapoli
t.dinapoli42 at gmail.com
Wed Apr 22 22:27:26 CEST 2015
This set of patches is what I am submitting as qualification for the google summer of code.
I wrote sse2/avx2 versions of several of the postprocessing filters
(namely the accurate deblock filter and all the deinterlace filters), and made several
changes to the structure of the postprocess_template.c file to support the new versions
of the fliters. However this is ultimately incomplete, I was unable to reproduce exactly
the same results using the sse2/avx2 fliters as obtained from the c/existing mmx2 filters.
The patches I'm submitting make all the changes necessary to use the new sse2/avx2 filters,
but by default they aren't used. This means all the patches should apply cleanly and pass
all the tests.
This qualification task has been more work that I'd anticapated and being a student I
haven't been able to put all the time into figuring out the problems as I would've liked.
I am confident that during the summer, without any other commitments, I will be able
to figure out the existing issues and fix them. I hope that dispite the obvious
issues you will still consider my accepting my project for the summer of code.
And now back to the original commit message:
Prefetching functions are defined in postprocess_template using the
RENAME macro so that prefetching is used when available. For x86
targets inline asm is used and the functions are non-empty only for
cpus where prefetching is available. For non x86 targets the gcc bultin
prefetch is used if it is available, otherwise no prefetching is done.
---
libpostproc/postprocess.c | 31 ---------
libpostproc/postprocess_template.c | 126 +++++++++++++++++++++----------------
2 files changed, 71 insertions(+), 86 deletions(-)
diff --git a/libpostproc/postprocess.c b/libpostproc/postprocess.c
index 9d89782..af70bb3 100644
--- a/libpostproc/postprocess.c
+++ b/libpostproc/postprocess.c
@@ -168,37 +168,6 @@ static const char * const replaceTable[]=
NULL //End Marker
};
-
-#if ARCH_X86 && HAVE_INLINE_ASM
-static inline void prefetchnta(const void *p)
-{
- __asm__ volatile( "prefetchnta (%0)\n\t"
- : : "r" (p)
- );
-}
-
-static inline void prefetcht0(const void *p)
-{
- __asm__ volatile( "prefetcht0 (%0)\n\t"
- : : "r" (p)
- );
-}
-
-static inline void prefetcht1(const void *p)
-{
- __asm__ volatile( "prefetcht1 (%0)\n\t"
- : : "r" (p)
- );
-}
-
-static inline void prefetcht2(const void *p)
-{
- __asm__ volatile( "prefetcht2 (%0)\n\t"
- : : "r" (p)
- );
-}
-#endif
-
/* The horizontal functions exist only in C because the MMX
* code is faster with vertical filters and transposing. */
diff --git a/libpostproc/postprocess_template.c b/libpostproc/postprocess_template.c
index 16e441a..e153b13 100644
--- a/libpostproc/postprocess_template.c
+++ b/libpostproc/postprocess_template.c
@@ -3242,6 +3242,69 @@ static inline void RENAME(duplicate)(uint8_t src[], int stride)
#endif
}
+#if ARCH_X86 && TEMPLATE_PP_MMXEXT
+static inline void RENAME(prefetchnta)(const void *p)
+{
+ __asm__ volatile( "prefetchnta (%0)\n\t"
+ : : "r" (p)
+ );
+}
+
+static inline void RENAME(prefetcht0)(const void *p)
+{
+ __asm__ volatile( "prefetcht0 (%0)\n\t"
+ : : "r" (p)
+ );
+}
+
+static inline void RENAME(prefetcht1)(const void *p)
+{
+ __asm__ volatile( "prefetcht1 (%0)\n\t"
+ : : "r" (p)
+ );
+}
+
+static inline void RENAME(prefetcht2)(const void *p)
+{
+ __asm__ volatile( "prefetcht2 (%0)\n\t"
+ : : "r" (p)
+ );
+}
+#elif !ARCH_X86 && AV_GCC_VERSION_AT_LEAST(3,2)
+static inline void RENAME(prefetchnta)(const void *p)
+{
+ __builtin_prefetch(p,0,0);
+}
+static inline void RENAME(prefetcht0)(const void *p)
+{
+ __builtin_prefetch(p,0,1);
+}
+static inline void RENAME(prefetcht1)(const void *p)
+{
+ __builtin_prefetch(p,0,2);
+}
+static inline void RENAME(prefetcht2)(const void *p)
+{
+ __builtin_prefetch(p,0,3);
+}
+#else
+static inline void RENAME(prefetchnta)(const void *p)
+{
+ return;
+}
+static inline void RENAME(prefetcht0)(const void *p)
+{
+ return;
+}
+static inline void RENAME(prefetcht1)(const void *p)
+{
+ return;
+}
+static inline void RENAME(prefetcht2)(const void *p)
+{
+ return;
+}
+#endif
/**
* Filter array of bytes (Y or U or V values)
*/
@@ -3368,34 +3431,10 @@ static void RENAME(postProcess)(const uint8_t src[], int srcStride, uint8_t dst[
// finish 1 block before the next otherwise we might have a problem
// with the L1 Cache of the P4 ... or only a few blocks at a time or something
for(x=0; x<width; x+=BLOCK_SIZE){
-
-#if TEMPLATE_PP_MMXEXT && HAVE_6REGS
-/*
- prefetchnta(srcBlock + (((x>>2)&6) + 5)*srcStride + 32);
- prefetchnta(srcBlock + (((x>>2)&6) + 6)*srcStride + 32);
- prefetcht0(dstBlock + (((x>>2)&6) + 5)*dstStride + 32);
- prefetcht0(dstBlock + (((x>>2)&6) + 6)*dstStride + 32);
-*/
-
- __asm__(
- "mov %4, %%"REG_a" \n\t"
- "shr $2, %%"REG_a" \n\t"
- "and $6, %%"REG_a" \n\t"
- "add %5, %%"REG_a" \n\t"
- "mov %%"REG_a", %%"REG_d" \n\t"
- "imul %1, %%"REG_a" \n\t"
- "imul %3, %%"REG_d" \n\t"
- "prefetchnta 32(%%"REG_a", %0) \n\t"
- "prefetcht0 32(%%"REG_d", %2) \n\t"
- "add %1, %%"REG_a" \n\t"
- "add %3, %%"REG_d" \n\t"
- "prefetchnta 32(%%"REG_a", %0) \n\t"
- "prefetcht0 32(%%"REG_d", %2) \n\t"
- :: "r" (srcBlock), "r" ((x86_reg)srcStride), "r" (dstBlock), "r" ((x86_reg)dstStride),
- "g" ((x86_reg)x), "g" ((x86_reg)copyAhead)
- : "%"REG_a, "%"REG_d
- );
-#endif
+ RENAME(prefetchnta)(srcBlock + (((x>>2)&6) + copyAhead)*srcStride + 32);
+ RENAME(prefetchnta)(srcBlock + (((x>>2)&6) + copyAhead+1)*srcStride + 32);
+ RENAME(prefetcht0)(dstBlock + (((x>>2)&6) + copyAhead)*dstStride + 32);
+ RENAME(prefetcht0)(dstBlock + (((x>>2)&6) + copyAhead+1)*dstStride + 32);
RENAME(blockCopy)(dstBlock + dstStride*8, dstStride,
srcBlock + srcStride*8, srcStride, mode & LEVEL_FIX, &c.packedYOffset);
@@ -3474,33 +3513,10 @@ static void RENAME(postProcess)(const uint8_t src[], int srcStride, uint8_t dst[
uint8_t *dstBlockStart = dstBlock;
const uint8_t *srcBlockStart = srcBlock;
for(; x < endx; x+=BLOCK_SIZE){
-#if TEMPLATE_PP_MMXEXT && HAVE_6REGS
-/*
- prefetchnta(srcBlock + (((x>>2)&6) + 5)*srcStride + 32);
- prefetchnta(srcBlock + (((x>>2)&6) + 6)*srcStride + 32);
- prefetcht0(dstBlock + (((x>>2)&6) + 5)*dstStride + 32);
- prefetcht0(dstBlock + (((x>>2)&6) + 6)*dstStride + 32);
-*/
-
- __asm__(
- "mov %4, %%"REG_a" \n\t"
- "shr $2, %%"REG_a" \n\t"
- "and $6, %%"REG_a" \n\t"
- "add %5, %%"REG_a" \n\t"
- "mov %%"REG_a", %%"REG_d" \n\t"
- "imul %1, %%"REG_a" \n\t"
- "imul %3, %%"REG_d" \n\t"
- "prefetchnta 32(%%"REG_a", %0) \n\t"
- "prefetcht0 32(%%"REG_d", %2) \n\t"
- "add %1, %%"REG_a" \n\t"
- "add %3, %%"REG_d" \n\t"
- "prefetchnta 32(%%"REG_a", %0) \n\t"
- "prefetcht0 32(%%"REG_d", %2) \n\t"
- :: "r" (srcBlock), "r" ((x86_reg)srcStride), "r" (dstBlock), "r" ((x86_reg)dstStride),
- "g" ((x86_reg)x), "g" ((x86_reg)copyAhead)
- : "%"REG_a, "%"REG_d
- );
-#endif
+ RENAME(prefetchnta)(srcBlock + (((x>>2)&6) + copyAhead)*srcStride + 32);
+ RENAME(prefetchnta)(srcBlock + (((x>>2)&6) + copyAhead+1)*srcStride + 32);
+ RENAME(prefetcht0)(dstBlock + (((x>>2)&6) + copyAhead)*dstStride + 32);
+ RENAME(prefetcht0)(dstBlock + (((x>>2)&6) + copyAhead+1)*dstStride + 32);
RENAME(blockCopy)(dstBlock + dstStride*copyAhead, dstStride,
srcBlock + srcStride*copyAhead, srcStride, mode & LEVEL_FIX, &c.packedYOffset);
--
2.3.5
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