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 --- arch/x86_64/kernel/setup.c | 1 + 1 file changed, 1 insertion(+) (limited to 'arch/x86_64/kernel/setup.c') diff --git a/arch/x86_64/kernel/setup.c b/arch/x86_64/kernel/setup.c index 8090a0a46882..46bf556efc30 100644 --- a/arch/x86_64/kernel/setup.c +++ b/arch/x86_64/kernel/setup.c @@ -1042,6 +1042,7 @@ static void __cpuinit init_intel(struct cpuinfo_x86 *c) if ((c->x86 == 0xf && c->x86_model >= 0x03) || (c->x86 == 0x6 && c->x86_model >= 0x0e)) set_bit(X86_FEATURE_CONSTANT_TSC, &c->x86_capability); + set_bit(X86_FEATURE_SYNC_RDTSC, &c->x86_capability); c->x86_max_cores = intel_num_cpu_cores(c); srat_detect_node(); -- cgit v1.2.2