[FFmpeg-devel] [PATCH] x86/cpu: add AV_CPU_FLAG_AVXSLOW flag
James Almer
jamrial at gmail.com
Sat May 23 03:17:26 CEST 2015
Signed-off-by: James Almer <jamrial at gmail.com>
---
doc/APIchanges | 3 +++
libavutil/cpu.c | 5 +++++
libavutil/cpu.h | 1 +
libavutil/version.h | 4 ++--
libavutil/x86/cpu.c | 17 ++++++++++++++---
5 files changed, 25 insertions(+), 5 deletions(-)
diff --git a/doc/APIchanges b/doc/APIchanges
index 3cca389..6fa40b2 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -15,6 +15,9 @@ libavutil: 2014-08-09
API changes, most recent first:
+2015-xx-xx - xxxxxxx - lavu 54.24.100 - cpu.h
+ Add AV_CPU_FLAG_AVXSLOW.
+
2015-05-13 - xxxxxxx - lavc 56.39.100 / 56.23.0
Add av_vda_default_init2.
diff --git a/libavutil/cpu.c b/libavutil/cpu.c
index 765577d..780368d 100644
--- a/libavutil/cpu.c
+++ b/libavutil/cpu.c
@@ -59,6 +59,7 @@ void av_force_cpu_flags(int arg){
AV_CPU_FLAG_SSE4 |
AV_CPU_FLAG_SSE42 |
AV_CPU_FLAG_AVX |
+ AV_CPU_FLAG_AVXSLOW |
AV_CPU_FLAG_XOP |
AV_CPU_FLAG_FMA3 |
AV_CPU_FLAG_FMA4 |
@@ -111,6 +112,7 @@ int av_parse_cpu_flags(const char *s)
#define CPUFLAG_SSE4 (AV_CPU_FLAG_SSE4 | CPUFLAG_SSSE3)
#define CPUFLAG_SSE42 (AV_CPU_FLAG_SSE42 | CPUFLAG_SSE4)
#define CPUFLAG_AVX (AV_CPU_FLAG_AVX | CPUFLAG_SSE42)
+#define CPUFLAG_AVXSLOW (AV_CPU_FLAG_AVXSLOW | CPUFLAG_AVX)
#define CPUFLAG_XOP (AV_CPU_FLAG_XOP | CPUFLAG_AVX)
#define CPUFLAG_FMA3 (AV_CPU_FLAG_FMA3 | CPUFLAG_AVX)
#define CPUFLAG_FMA4 (AV_CPU_FLAG_FMA4 | CPUFLAG_AVX)
@@ -133,6 +135,7 @@ int av_parse_cpu_flags(const char *s)
{ "sse4.1" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = CPUFLAG_SSE4 }, .unit = "flags" },
{ "sse4.2" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = CPUFLAG_SSE42 }, .unit = "flags" },
{ "avx" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = CPUFLAG_AVX }, .unit = "flags" },
+ { "avxslow" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = CPUFLAG_AVXSLOW }, .unit = "flags" },
{ "xop" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = CPUFLAG_XOP }, .unit = "flags" },
{ "fma3" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = CPUFLAG_FMA3 }, .unit = "flags" },
{ "fma4" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = CPUFLAG_FMA4 }, .unit = "flags" },
@@ -192,6 +195,7 @@ int av_parse_cpu_caps(unsigned *flags, const char *s)
{ "sse4.1" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_SSE4 }, .unit = "flags" },
{ "sse4.2" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_SSE42 }, .unit = "flags" },
{ "avx" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_AVX }, .unit = "flags" },
+ { "avxslow" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_AVXSLOW }, .unit = "flags" },
{ "xop" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_XOP }, .unit = "flags" },
{ "fma3" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_FMA3 }, .unit = "flags" },
{ "fma4" , NULL, 0, AV_OPT_TYPE_CONST, { .i64 = AV_CPU_FLAG_FMA4 }, .unit = "flags" },
@@ -320,6 +324,7 @@ static const struct {
{ AV_CPU_FLAG_SSE4, "sse4.1" },
{ AV_CPU_FLAG_SSE42, "sse4.2" },
{ AV_CPU_FLAG_AVX, "avx" },
+ { AV_CPU_FLAG_AVXSLOW, "avxslow" },
{ AV_CPU_FLAG_XOP, "xop" },
{ AV_CPU_FLAG_FMA3, "fma3" },
{ AV_CPU_FLAG_FMA4, "fma4" },
diff --git a/libavutil/cpu.h b/libavutil/cpu.h
index 277e489..10b7136 100644
--- a/libavutil/cpu.h
+++ b/libavutil/cpu.h
@@ -43,6 +43,7 @@
#define AV_CPU_FLAG_SSE4 0x0100 ///< Penryn SSE4.1 functions
#define AV_CPU_FLAG_SSE42 0x0200 ///< Nehalem SSE4.2 functions
#define AV_CPU_FLAG_AVX 0x4000 ///< AVX functions: requires OS support even if YMM registers aren't used
+#define AV_CPU_FLAG_AVXSLOW 0x8000000 ///< AVX supported, but slow when using YMM registers (e.g. Bulldozer)
#define AV_CPU_FLAG_XOP 0x0400 ///< Bulldozer XOP functions
#define AV_CPU_FLAG_FMA4 0x0800 ///< Bulldozer FMA4 functions
// #if LIBAVUTIL_VERSION_MAJOR <52
diff --git a/libavutil/version.h b/libavutil/version.h
index 18a2295..eeafcfa 100644
--- a/libavutil/version.h
+++ b/libavutil/version.h
@@ -56,8 +56,8 @@
*/
#define LIBAVUTIL_VERSION_MAJOR 54
-#define LIBAVUTIL_VERSION_MINOR 23
-#define LIBAVUTIL_VERSION_MICRO 101
+#define LIBAVUTIL_VERSION_MINOR 24
+#define LIBAVUTIL_VERSION_MICRO 100
#define LIBAVUTIL_VERSION_INT AV_VERSION_INT(LIBAVUTIL_VERSION_MAJOR, \
LIBAVUTIL_VERSION_MINOR, \
diff --git a/libavutil/x86/cpu.c b/libavutil/x86/cpu.c
index 2b62e92..7a5d4e6 100644
--- a/libavutil/x86/cpu.c
+++ b/libavutil/x86/cpu.c
@@ -167,6 +167,7 @@ int ff_get_cpu_flags_x86(void)
if (ext_caps & (1 << 22))
rval |= AV_CPU_FLAG_MMXEXT;
+ if (!strncmp(vendor.c, "AuthenticAMD", 12)) {
/* Allow for selectively disabling SSE2 functions on AMD processors
with SSE2 support but not SSE4a. This includes Athlon64, some
Opteron, and some Sempron processors. MMX, SSE, or 3DNow! are faster
@@ -174,9 +175,19 @@ int ff_get_cpu_flags_x86(void)
AV_CPU_FLAG_SSE2 and AV_CPU_FLAG_SSE2SLOW are both set in this case
so that SSE2 is used unless explicitly disabled by checking
AV_CPU_FLAG_SSE2SLOW. */
- if (!strncmp(vendor.c, "AuthenticAMD", 12) &&
- rval & AV_CPU_FLAG_SSE2 && !(ecx & 0x00000040)) {
- rval |= AV_CPU_FLAG_SSE2SLOW;
+ if (rval & AV_CPU_FLAG_SSE2 && !(ecx & 0x00000040))
+ rval |= AV_CPU_FLAG_SSE2SLOW;
+
+ /* Similar to the above but for AVX functions on AMD processors.
+ This is necessary only for functions using YMM registers on Bulldozer
+ based CPUs as they lack 256-bits execution units. SSE/AVX functions
+ using XMM registers are always faster on them.
+ AV_CPU_FLAG_AVX and AV_CPU_FLAG_AVXSLOW are both set so that AVX is
+ used unless explicitly disabled by checking AV_CPU_FLAG_AVXSLOW.
+ TODO: Confirm if Excavator is affected or not by this once it's
+ released, and update the check if necessary. Same for btver2. */
+ if (family == 0x15 && (rval & AV_CPU_FLAG_AVX))
+ rval |= AV_CPU_FLAG_AVXSLOW;
}
/* XOP and FMA4 use the AVX instruction coding scheme, so they can't be
--
2.4.1
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