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authorH.J. Lu <hjl.tools@gmail.com>2015-01-30 06:50:20 -0800
committerH.J. Lu <hjl.tools@gmail.com>2015-01-30 12:26:33 -0800
commit328fc20e5e334a642f0152d9662474789381a897 (patch)
tree6efc6b6b150d1373c36c8bdaf4a606989c152a9a
parentf80af76648ed97a76745fad6caa3315a79cb1c7c (diff)
downloadglibc-hjl/release/2.20/master.tar.gz
Use AVX unaligned memcpy only if AVX2 is availablehjl/release/2.20/master
memcpy with unaligned 256-bit AVX register loads/stores are slow on older processorsl like Sandy Bridge. This patch adds bit_AVX_Fast_Unaligned_Load and sets it only when AVX2 is available. [BZ #17801] * sysdeps/x86_64/multiarch/init-arch.c (__init_cpu_features): Set the bit_AVX_Fast_Unaligned_Load bit for AVX2. * sysdeps/x86_64/multiarch/init-arch.h (bit_AVX_Fast_Unaligned_Load): New. (index_AVX_Fast_Unaligned_Load): Likewise. (HAS_AVX_FAST_UNALIGNED_LOAD): Likewise. * sysdeps/x86_64/multiarch/memcpy.S (__new_memcpy): Check the bit_AVX_Fast_Unaligned_Load bit instead of the bit_AVX_Usable bit. * sysdeps/x86_64/multiarch/memcpy_chk.S (__memcpy_chk): Likewise. * sysdeps/x86_64/multiarch/mempcpy.S (__mempcpy): Likewise. * sysdeps/x86_64/multiarch/mempcpy_chk.S (__mempcpy_chk): Likewise. * sysdeps/x86_64/multiarch/memmove.c (__libc_memmove): Replace HAS_AVX with HAS_AVX_FAST_UNALIGNED_LOAD. * sysdeps/x86_64/multiarch/memmove_chk.c (__memmove_chk): Likewise. [cherry picked from commit 56d25c11b64a97255a115901d136d753c86de24e]
Diffstat
-rw-r--r--sysdeps/x86_64/multiarch/init-arch.c9
-rw-r--r--sysdeps/x86_64/multiarch/init-arch.h4
-rw-r--r--sysdeps/x86_64/multiarch/memcpy.S2
-rw-r--r--sysdeps/x86_64/multiarch/memcpy_chk.S2
-rw-r--r--sysdeps/x86_64/multiarch/memmove.c2
-rw-r--r--sysdeps/x86_64/multiarch/memmove_chk.c2
-rw-r--r--sysdeps/x86_64/multiarch/mempcpy.S2
-rw-r--r--sysdeps/x86_64/multiarch/mempcpy_chk.S2
8 files changed, 17 insertions, 8 deletions
diff --git a/sysdeps/x86_64/multiarch/init-arch.c b/sysdeps/x86_64/multiarch/init-arch.c
index 2a6dcb78d8..f7c1bbe0db 100644
--- a/sysdeps/x86_64/multiarch/init-arch.c
+++ b/sysdeps/x86_64/multiarch/init-arch.c
@@ -167,9 +167,14 @@ __init_cpu_features (void)
/* Determine if AVX is usable. */
if (CPUID_AVX)
__cpu_features.feature[index_AVX_Usable] |= bit_AVX_Usable;
- /* Determine if AVX2 is usable. */
+#if index_AVX2_Usable != index_AVX_Fast_Unaligned_Load
+# error index_AVX2_Usable != index_AVX_Fast_Unaligned_Load
+#endif
+ /* Determine if AVX2 is usable. Unaligned load with 256-bit
+ AVX registers are faster on processors with AVX2. */
if (CPUID_AVX2)
- __cpu_features.feature[index_AVX2_Usable] |= bit_AVX2_Usable;
+ __cpu_features.feature[index_AVX2_Usable]
+ |= bit_AVX2_Usable | bit_AVX_Fast_Unaligned_Load;
/* Determine if FMA is usable. */
if (CPUID_FMA)
__cpu_features.feature[index_FMA_Usable] |= bit_FMA_Usable;
diff --git a/sysdeps/x86_64/multiarch/init-arch.h b/sysdeps/x86_64/multiarch/init-arch.h
index ef0abbd226..2fc7c7ceec 100644
--- a/sysdeps/x86_64/multiarch/init-arch.h
+++ b/sysdeps/x86_64/multiarch/init-arch.h
@@ -25,6 +25,7 @@
#define bit_FMA4_Usable (1 << 8)
#define bit_Slow_SSE4_2 (1 << 9)
#define bit_AVX2_Usable (1 << 10)
+#define bit_AVX_Fast_Unaligned_Load (1 << 11)
/* CPUID Feature flags. */
@@ -74,6 +75,7 @@
# define index_FMA4_Usable FEATURE_INDEX_1*FEATURE_SIZE
# define index_Slow_SSE4_2 FEATURE_INDEX_1*FEATURE_SIZE
# define index_AVX2_Usable FEATURE_INDEX_1*FEATURE_SIZE
+# define index_AVX_Fast_Unaligned_Load FEATURE_INDEX_1*FEATURE_SIZE
#else /* __ASSEMBLER__ */
@@ -169,6 +171,7 @@ extern const struct cpu_features *__get_cpu_features (void)
# define index_FMA4_Usable FEATURE_INDEX_1
# define index_Slow_SSE4_2 FEATURE_INDEX_1
# define index_AVX2_Usable FEATURE_INDEX_1
+# define index_AVX_Fast_Unaligned_Load FEATURE_INDEX_1
# define HAS_ARCH_FEATURE(name) \
((__get_cpu_features ()->feature[index_##name] & (bit_##name)) != 0)
@@ -181,5 +184,6 @@ extern const struct cpu_features *__get_cpu_features (void)
# define HAS_AVX2 HAS_ARCH_FEATURE (AVX2_Usable)
# define HAS_FMA HAS_ARCH_FEATURE (FMA_Usable)
# define HAS_FMA4 HAS_ARCH_FEATURE (FMA4_Usable)
+# define HAS_AVX_FAST_UNALIGNED_LOAD HAS_ARCH_FEATURE (AVX_Fast_Unaligned_Load)
#endif /* __ASSEMBLER__ */
diff --git a/sysdeps/x86_64/multiarch/memcpy.S b/sysdeps/x86_64/multiarch/memcpy.S
index e666695407..10bbd39631 100644
--- a/sysdeps/x86_64/multiarch/memcpy.S
+++ b/sysdeps/x86_64/multiarch/memcpy.S
@@ -33,7 +33,7 @@ ENTRY(__new_memcpy)
jne 1f
call __init_cpu_features
1: leaq __memcpy_avx_unaligned(%rip), %rax
- testl $bit_AVX_Usable, __cpu_features+FEATURE_OFFSET+index_AVX_Usable(%rip)
+ testl $bit_AVX_Fast_Unaligned_Load, __cpu_features+FEATURE_OFFSET+index_AVX_Fast_Unaligned_Load(%rip)
jz 1f
ret
1: leaq __memcpy_sse2(%rip), %rax
diff --git a/sysdeps/x86_64/multiarch/memcpy_chk.S b/sysdeps/x86_64/multiarch/memcpy_chk.S
index 076b19a9ea..30cca20330 100644
--- a/sysdeps/x86_64/multiarch/memcpy_chk.S
+++ b/sysdeps/x86_64/multiarch/memcpy_chk.S
@@ -39,7 +39,7 @@ ENTRY(__memcpy_chk)
testl $bit_Fast_Copy_Backward, __cpu_features+FEATURE_OFFSET+index_Fast_Copy_Backward(%rip)
jz 2f
leaq __memcpy_chk_ssse3_back(%rip), %rax
- testl $bit_AVX_Usable, __cpu_features+FEATURE_OFFSET+index_AVX_Usable(%rip)
+ testl $bit_AVX_Fast_Unaligned_Load, __cpu_features+FEATURE_OFFSET+index_AVX_Fast_Unaligned_Load(%rip)
jz 2f
leaq __memcpy_chk_avx_unaligned(%rip), %rax
2: ret
diff --git a/sysdeps/x86_64/multiarch/memmove.c b/sysdeps/x86_64/multiarch/memmove.c
index 0c9af7e4df..2c86a4a476 100644
--- a/sysdeps/x86_64/multiarch/memmove.c
+++ b/sysdeps/x86_64/multiarch/memmove.c
@@ -49,7 +49,7 @@ extern __typeof (__redirect_memmove) __memmove_avx_unaligned attribute_hidden;
ifunc symbol properly. */
extern __typeof (__redirect_memmove) __libc_memmove;
libc_ifunc (__libc_memmove,
- HAS_AVX
+ HAS_AVX_FAST_UNALIGNED_LOAD
? __memmove_avx_unaligned
: (HAS_SSSE3
? (HAS_FAST_COPY_BACKWARD
diff --git a/sysdeps/x86_64/multiarch/memmove_chk.c b/sysdeps/x86_64/multiarch/memmove_chk.c
index 44344f2820..5ffcaecce4 100644
--- a/sysdeps/x86_64/multiarch/memmove_chk.c
+++ b/sysdeps/x86_64/multiarch/memmove_chk.c
@@ -30,7 +30,7 @@ extern __typeof (__memmove_chk) __memmove_chk_avx_unaligned attribute_hidden;
#include "debug/memmove_chk.c"
libc_ifunc (__memmove_chk,
- HAS_AVX ? __memmove_chk_avx_unaligned :
+ HAS_AVX_FAST_UNALIGNED_LOAD ? __memmove_chk_avx_unaligned :
(HAS_SSSE3
? (HAS_FAST_COPY_BACKWARD
? __memmove_chk_ssse3_back : __memmove_chk_ssse3)
diff --git a/sysdeps/x86_64/multiarch/mempcpy.S b/sysdeps/x86_64/multiarch/mempcpy.S
index 7589d8c1ec..e205ef5557 100644
--- a/sysdeps/x86_64/multiarch/mempcpy.S
+++ b/sysdeps/x86_64/multiarch/mempcpy.S
@@ -37,7 +37,7 @@ ENTRY(__mempcpy)
testl $bit_Fast_Copy_Backward, __cpu_features+FEATURE_OFFSET+index_Fast_Copy_Backward(%rip)
jz 2f
leaq __mempcpy_ssse3_back(%rip), %rax
- testl $bit_AVX_Usable, __cpu_features+FEATURE_OFFSET+index_AVX_Usable(%rip)
+ testl $bit_AVX_Fast_Unaligned_Load, __cpu_features+FEATURE_OFFSET+index_AVX_Fast_Unaligned_Load(%rip)
jz 2f
leaq __mempcpy_avx_unaligned(%rip), %rax
2: ret
diff --git a/sysdeps/x86_64/multiarch/mempcpy_chk.S b/sysdeps/x86_64/multiarch/mempcpy_chk.S
index 88e0b74e83..dd777dfa48 100644
--- a/sysdeps/x86_64/multiarch/mempcpy_chk.S
+++ b/sysdeps/x86_64/multiarch/mempcpy_chk.S
@@ -39,7 +39,7 @@ ENTRY(__mempcpy_chk)
testl $bit_Fast_Copy_Backward, __cpu_features+FEATURE_OFFSET+index_Fast_Copy_Backward(%rip)
jz 2f
leaq __mempcpy_chk_ssse3_back(%rip), %rax
- testl $bit_AVX_Usable, __cpu_features+FEATURE_OFFSET+index_AVX_Usable(%rip)
+ testl $bit_AVX_Fast_Unaligned_Load, __cpu_features+FEATURE_OFFSET+index_AVX_Fast_Unaligned_Load(%rip)
jz 2f
leaq __mempcpy_chk_avx_unaligned(%rip), %rax
2: ret
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