[vlc-commits] copy: minor speed enhancement to USWC copy
Jean-Yves Avenard
git at videolan.org
Mon Jun 16 09:51:17 CEST 2014
vlc | branch: master | Jean-Yves Avenard <jyavenard at mythtv.org> | Sun Jun 15 09:04:37 2014 +0000| [b50a07a3ee8728c602d88432365aae67abc81b28] | committer: Jean-Baptiste Kempf
copy: minor speed enhancement to USWC copy
Adopt suggestions as per https://software.intel.com/en-us/articles/copying-accelerated-video-decode-frame-buffers:
- 64kB aligned memory buffer
- Call to mfence only around copy to cache routine.
Use a single instruction to copy non-aligned memory at startup.
Remove compilation warning on mac
This result in a small 1.3% speed increase on an i7-4650U
Signed-off-by: Jean-Baptiste Kempf <jb at videolan.org>
> http://git.videolan.org/gitweb.cgi/vlc.git/?a=commit;h=b50a07a3ee8728c602d88432365aae67abc81b28
---
modules/video_chroma/copy.c | 41 +++++++++++++++++++++++------------------
1 file changed, 23 insertions(+), 18 deletions(-)
diff --git a/modules/video_chroma/copy.c b/modules/video_chroma/copy.c
index d29843c..cc98c92 100644
--- a/modules/video_chroma/copy.c
+++ b/modules/video_chroma/copy.c
@@ -35,8 +35,8 @@
int CopyInitCache(copy_cache_t *cache, unsigned width)
{
#ifdef CAN_COMPILE_SSE2
- cache->size = __MAX((width + 0x0f) & ~ 0x0f, 4096);
- cache->buffer = vlc_memalign(16, cache->size);
+ cache->size = __MAX((width + 0x3f) & ~ 0x3f, 4096);
+ cache->buffer = vlc_memalign(64, cache->size);
if (!cache->buffer)
return VLC_EGENERIC;
#else
@@ -57,9 +57,15 @@ void CopyCleanCache(copy_cache_t *cache)
}
#ifdef CAN_COMPILE_SSE2
-/* Copy 64 bytes from srcp to dstp loading data with the SSE>=2 instruction
+/* Copy 16/64 bytes from srcp to dstp loading data with the SSE>=2 instruction
* load and storing data with the SSE>=2 instruction store.
*/
+#define COPY16(dstp, srcp, load, store) \
+ asm volatile ( \
+ load " 0(%[src]), %%xmm1\n" \
+ store " %%xmm1, 0(%[dst])\n" \
+ : : [dst]"r"(dstp), [src]"r"(srcp) : "memory", "xmm1")
+
#define COPY64(dstp, srcp, load, store) \
asm volatile ( \
load " 0(%[src]), %%xmm1\n" \
@@ -97,16 +103,16 @@ static void CopyFromUswc(uint8_t *dst, size_t dst_pitch,
unsigned width, unsigned height,
unsigned cpu)
{
+#ifndef CAN_COMPILE_SSSE3
+ VLC_UNUSED(cpu);
+#endif
assert(((intptr_t)dst & 0x0f) == 0 && (dst_pitch & 0x0f) == 0);
asm volatile ("mfence");
for (unsigned y = 0; y < height; y++) {
const unsigned unaligned = (-(uintptr_t)src) & 0x0f;
- unsigned x = 0;
-
- for (; x < unaligned; x++)
- dst[x] = src[x];
+ unsigned x = unaligned;
#ifdef CAN_COMPILE_SSE4_1
if (vlc_CPU_SSE4_1()) {
@@ -114,6 +120,7 @@ static void CopyFromUswc(uint8_t *dst, size_t dst_pitch,
for (; x+63 < width; x += 64)
COPY64(&dst[x], &src[x], "movntdqa", "movdqa");
} else {
+ COPY16(dst, src, "movdqu", "movdqa");
for (; x+63 < width; x += 64)
COPY64(&dst[x], &src[x], "movntdqa", "movdqu");
}
@@ -124,6 +131,7 @@ static void CopyFromUswc(uint8_t *dst, size_t dst_pitch,
for (; x+63 < width; x += 64)
COPY64(&dst[x], &src[x], "movdqa", "movdqa");
} else {
+ COPY16(dst, src, "movdqu", "movdqa");
for (; x+63 < width; x += 64)
COPY64(&dst[x], &src[x], "movdqa", "movdqu");
}
@@ -135,6 +143,7 @@ static void CopyFromUswc(uint8_t *dst, size_t dst_pitch,
src += src_pitch;
dst += dst_pitch;
}
+ asm volatile ("mfence");
}
VLC_SSE
@@ -144,8 +153,6 @@ static void Copy2d(uint8_t *dst, size_t dst_pitch,
{
assert(((intptr_t)src & 0x0f) == 0 && (src_pitch & 0x0f) == 0);
- asm volatile ("mfence");
-
for (unsigned y = 0; y < height; y++) {
unsigned x = 0;
@@ -172,15 +179,15 @@ static void SSE_SplitUV(uint8_t *dstu, size_t dstu_pitch,
const uint8_t *src, size_t src_pitch,
unsigned width, unsigned height, unsigned cpu)
{
+#ifndef CAN_COMPILE_SSSE3
VLC_UNUSED(cpu);
+#endif
const uint8_t shuffle[] = { 0, 2, 4, 6, 8, 10, 12, 14,
1, 3, 5, 7, 9, 11, 13, 15 };
const uint8_t mask[] = { 0xff, 0x00, 0xff, 0x00, 0xff, 0x00, 0xff, 0x00,
0xff, 0x00, 0xff, 0x00, 0xff, 0x00, 0xff, 0x00 };
- assert(((intptr_t)src & 0x0f) == 0 && (src_pitch & 0x0f) == 0);
-
- asm volatile ("mfence");
+ assert(((intptr_t)src & 0xf) == 0 && (src_pitch & 0x0f) == 0);
for (unsigned y = 0; y < height; y++) {
unsigned x = 0;
@@ -280,7 +287,6 @@ static void SSE_CopyPlane(uint8_t *dst, size_t dst_pitch,
src += src_pitch * hblock;
dst += dst_pitch * hblock;
}
- asm volatile ("mfence");
}
static void SSE_SplitPlanes(uint8_t *dstu, size_t dstu_pitch,
@@ -289,27 +295,26 @@ static void SSE_SplitPlanes(uint8_t *dstu, size_t dstu_pitch,
uint8_t *cache, size_t cache_size,
unsigned width, unsigned height, unsigned cpu)
{
- const unsigned w2_16 = (2*width+15) & ~15;
- const unsigned hstep = cache_size / w2_16;
+ const unsigned w16 = (2*width+15) & ~15;
+ const unsigned hstep = cache_size / w16;
assert(hstep > 0);
for (unsigned y = 0; y < height; y += hstep) {
const unsigned hblock = __MIN(hstep, height - y);
/* Copy a bunch of line into our cache */
- CopyFromUswc(cache, w2_16, src, src_pitch,
+ CopyFromUswc(cache, w16, src, src_pitch,
2*width, hblock, cpu);
/* Copy from our cache to the destination */
SSE_SplitUV(dstu, dstu_pitch, dstv, dstv_pitch,
- cache, w2_16, width, hblock, cpu);
+ cache, w16, width, hblock, cpu);
/* */
src += src_pitch * hblock;
dstu += dstu_pitch * hblock;
dstv += dstv_pitch * hblock;
}
- asm volatile ("mfence");
}
static void SSE_CopyFromNv12(picture_t *dst,
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