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| author | H.J. Lu <hjl.tools@gmail.com> | 2016-03-28 04:39:48 -0700 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2016-03-28 04:40:03 -0700 |
| commit | e41b395523040fcb58c7d378475720c2836d280c (patch) | |
| tree | 7a4271638219c8d5b141039178105b0f1564ea16 /sysdeps/x86/cpu-features.h | |
| parent | b66d837bb5398795c6b0f651bd5a5d66091d8577 (diff) | |
| download | glibc-e41b395523040fcb58c7d378475720c2836d280c.zip glibc-e41b395523040fcb58c7d378475720c2836d280c.tar.gz glibc-e41b395523040fcb58c7d378475720c2836d280c.tar.bz2 | |
[x86] Add a feature bit: Fast_Unaligned_Copy
On AMD processors, memcpy optimized with unaligned SSE load is
slower than emcpy optimized with aligned SSSE3 while other string
functions are faster with unaligned SSE load. A feature bit,
Fast_Unaligned_Copy, is added to select memcpy optimized with
unaligned SSE load.
[BZ #19583]
* sysdeps/x86/cpu-features.c (init_cpu_features): Set
Fast_Unaligned_Copy with Fast_Unaligned_Load for Intel
processors. Set Fast_Copy_Backward for AMD Excavator
processors.
* sysdeps/x86/cpu-features.h (bit_arch_Fast_Unaligned_Copy):
New.
(index_arch_Fast_Unaligned_Copy): Likewise.
* sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Check
Fast_Unaligned_Copy instead of Fast_Unaligned_Load.
Diffstat (limited to 'sysdeps/x86/cpu-features.h')
| -rw-r--r-- | sysdeps/x86/cpu-features.h | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h index e06eb7e..bfe1f4c 100644 --- a/sysdeps/x86/cpu-features.h +++ b/sysdeps/x86/cpu-features.h @@ -35,6 +35,7 @@ #define bit_arch_I686 (1 << 15) #define bit_arch_Prefer_MAP_32BIT_EXEC (1 << 16) #define bit_arch_Prefer_No_VZEROUPPER (1 << 17) +#define bit_arch_Fast_Unaligned_Copy (1 << 18) /* CPUID Feature flags. */ @@ -101,6 +102,7 @@ # define index_arch_I686 FEATURE_INDEX_1*FEATURE_SIZE # define index_arch_Prefer_MAP_32BIT_EXEC FEATURE_INDEX_1*FEATURE_SIZE # define index_arch_Prefer_No_VZEROUPPER FEATURE_INDEX_1*FEATURE_SIZE +# define index_arch_Fast_Unaligned_Copy FEATURE_INDEX_1*FEATURE_SIZE # if defined (_LIBC) && !IS_IN (nonlib) @@ -265,6 +267,7 @@ extern const struct cpu_features *__get_cpu_features (void) # define index_arch_I686 FEATURE_INDEX_1 # define index_arch_Prefer_MAP_32BIT_EXEC FEATURE_INDEX_1 # define index_arch_Prefer_No_VZEROUPPER FEATURE_INDEX_1 +# define index_arch_Fast_Unaligned_Copy FEATURE_INDEX_1 #endif /* !__ASSEMBLER__ */ |