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| author |   Andi Kleen <ak@suse.de> | 2006-01-11 22:45:24 +0100 |
|---|---|---|
| committer |   Linus Torvalds <torvalds@g5.osdl.org> | 2006-01-11 19:04:58 -0800 |
| commit | c818a18146997d1356a4840b0c01f1168c16c8a4 (patch) | |
| tree | 8d7e049742e87666bf3089fe46e04828b6417fd7 /include/asm-x86_64/cpufeature.h | |
| parent | [PATCH] x86_64: Support alternative() in vsyscalls (diff) | |
| download | linux-dev-c818a18146997d1356a4840b0c01f1168c16c8a4.tar.xz linux-dev-c818a18146997d1356a4840b0c01f1168c16c8a4.zip | |
[PATCH] x86_64: On Intel CPUs don't do an additional CPU sync before RDTSC
RDTSC serialization using cpuid is not needed for Intel platforms.
This increases gettimeofday performance.
Cc: vojtech@suse.cz
Cc: rohit.seth@intel.com
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/asm-x86_64/cpufeature.h')
| -rw-r--r-- | include/asm-x86_64/cpufeature.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/asm-x86_64/cpufeature.h b/include/asm-x86_64/cpufeature.h index aea308c65709..72b39f514798 100644 --- a/include/asm-x86_64/cpufeature.h +++ b/include/asm-x86_64/cpufeature.h @@ -63,6 +63,7 @@ #define X86_FEATURE_CENTAUR_MCR (3*32+ 3) /* Centaur MCRs (= MTRRs) */ #define X86_FEATURE_K8_C (3*32+ 4) /* C stepping K8 */ #define X86_FEATURE_CONSTANT_TSC (3*32+5) /* TSC runs at constant rate */ +#define X86_FEATURE_SYNC_RDTSC (3*32+6) /* RDTSC syncs CPU core */ /* Intel-defined CPU features, CPUID level 0x00000001 (ecx), word 4 */ #define X86_FEATURE_XMM3 (4*32+ 0) /* Streaming SIMD Extensions-3 */ |