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| author | Ling Ma <ling.ml@alibaba-inc.com> | 2014-07-14 00:02:52 -0400 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2014-07-30 08:02:35 -0700 |
| commit | 05f3633da4f9df870d04dd77336e793746e57ed4 (patch) | |
| tree | bd980df4702ffd9ebfa9cb4dac8823a659f0c430 /sysdeps/x86_64/multiarch/mempcpy.S | |
| parent | a53fbd8e6cd2f69bdfa3431d616a5f332aea6664 (diff) | |
| download | glibc-05f3633da4f9df870d04dd77336e793746e57ed4.tar.gz glibc-05f3633da4f9df870d04dd77336e793746e57ed4.tar.xz glibc-05f3633da4f9df870d04dd77336e793746e57ed4.zip | |
Improve 64bit memcpy performance for Haswell CPU with AVX instruction
In this patch we take advantage of HSW memory bandwidth, manage to reduce miss branch prediction by avoiding using branch instructions and force destination to be aligned with avx instruction. The CPU2006 403.gcc benchmark indicates this patch improves performance from 2% to 10%.
Diffstat (limited to 'sysdeps/x86_64/multiarch/mempcpy.S')
| -rw-r--r-- | sysdeps/x86_64/multiarch/mempcpy.S | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/sysdeps/x86_64/multiarch/mempcpy.S b/sysdeps/x86_64/multiarch/mempcpy.S index b9f04c2ec4..7589d8c1ec 100644 --- a/sysdeps/x86_64/multiarch/mempcpy.S +++ b/sysdeps/x86_64/multiarch/mempcpy.S @@ -37,6 +37,9 @@ 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) + jz 2f + leaq __mempcpy_avx_unaligned(%rip), %rax 2: ret END(__mempcpy) |