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authorH.J. Lu <hjl.tools@gmail.com>2016-03-23 10:33:19 -0700
committerH.J. Lu <hjl.tools@gmail.com>2016-03-23 10:56:38 -0700
commit327aadf6348bd41d1fae46ee7780e214c0a493c1 (patch)
tree3a1f3550ee36ea010e53e1ad8f4e1ffc450b5c18
parent7a25d6a84df9fea56963569ceccaaf7c2a88f161 (diff)
downloadtermbaud-hjl/pr19583.tar.gz
termbaud-hjl/pr19583.tar.xz
termbaud-hjl/pr19583.zip
[x86] Add a feature bit: Fast_Unaligned_Copyhjl/pr19583
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.
-rw-r--r--sysdeps/x86/cpu-features.c14
-rw-r--r--sysdeps/x86/cpu-features.h3
-rw-r--r--sysdeps/x86_64/multiarch/memcpy.S2
3 files changed, 17 insertions, 2 deletions
diff --git a/sysdeps/x86/cpu-features.c b/sysdeps/x86/cpu-features.c
index c8f81efd03b..de75c79cf98 100644
--- a/sysdeps/x86/cpu-features.c
+++ b/sysdeps/x86/cpu-features.c
@@ -153,8 +153,12 @@ init_cpu_features (struct cpu_features *cpu_features)
#if index_arch_Fast_Unaligned_Load != index_arch_Slow_SSE4_2
# error index_arch_Fast_Unaligned_Load != index_arch_Slow_SSE4_2
#endif
+#if index_arch_Fast_Unaligned_Load != index_arch_Fast_Unaligned_Copy
+# error index_arch_Fast_Unaligned_Load != index_arch_Fast_Unaligned_Copy
+#endif
cpu_features->feature[index_arch_Fast_Unaligned_Load]
|= (bit_arch_Fast_Unaligned_Load
+ | bit_arch_Fast_Unaligned_Copy
| bit_arch_Prefer_PMINUB_for_stringop
| bit_arch_Slow_SSE4_2);
break;
@@ -183,10 +187,14 @@ init_cpu_features (struct cpu_features *cpu_features)
#if index_arch_Fast_Rep_String != index_arch_Prefer_PMINUB_for_stringop
# error index_arch_Fast_Rep_String != index_arch_Prefer_PMINUB_for_stringop
#endif
+#if index_arch_Fast_Rep_String != index_arch_Fast_Unaligned_Copy
+# error index_arch_Fast_Rep_String != index_arch_Fast_Unaligned_Copy
+#endif
cpu_features->feature[index_arch_Fast_Rep_String]
|= (bit_arch_Fast_Rep_String
| bit_arch_Fast_Copy_Backward
| bit_arch_Fast_Unaligned_Load
+ | bit_arch_Fast_Unaligned_Copy
| bit_arch_Prefer_PMINUB_for_stringop);
break;
}
@@ -220,10 +228,14 @@ init_cpu_features (struct cpu_features *cpu_features)
if (family == 0x15)
{
+#if index_arch_Fast_Unaligned_Load != index_arch_Fast_Copy_Backward
+# error index_arch_Fast_Unaligned_Load != index_arch_Fast_Copy_Backward
+#endif
/* "Excavator" */
if (model >= 0x60 && model <= 0x7f)
cpu_features->feature[index_arch_Fast_Unaligned_Load]
- |= bit_arch_Fast_Unaligned_Load;
+ |= (bit_arch_Fast_Unaligned_Load
+ | bit_arch_Fast_Copy_Backward);
}
}
else
diff --git a/sysdeps/x86/cpu-features.h b/sysdeps/x86/cpu-features.h
index e06eb7e41b8..bfe1f4c68d5 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__ */
diff --git a/sysdeps/x86_64/multiarch/memcpy.S b/sysdeps/x86_64/multiarch/memcpy.S
index 8882590e511..5b045d7847d 100644
--- a/sysdeps/x86_64/multiarch/memcpy.S
+++ b/sysdeps/x86_64/multiarch/memcpy.S
@@ -42,7 +42,7 @@ ENTRY(__new_memcpy)
HAS_ARCH_FEATURE (AVX_Fast_Unaligned_Load)
jnz 2f
lea __memcpy_sse2_unaligned(%rip), %RAX_LP
- HAS_ARCH_FEATURE (Fast_Unaligned_Load)
+ HAS_ARCH_FEATURE (Fast_Unaligned_Copy)
jnz 2f
lea __memcpy_sse2(%rip), %RAX_LP
HAS_CPU_FEATURE (SSSE3)