From c818a18146997d1356a4840b0c01f1168c16c8a4 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Wed, 11 Jan 2006 22:45:24 +0100 Subject: [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 Signed-off-by: Linus Torvalds --- include/asm-x86_64/cpufeature.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/asm-x86_64/cpufeature.h') 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 */ -- cgit v1.2.3-59-g8ed1b