Commit e4cff6ac authored Apr 11, 2006 by Siddha, Suresh B Committed by Linus Torvalds Apr 11, 2006

[PATCH] x86_64: fix sync before RDTSC on Intel cpus



Commit c818a181 didn't do the expected
thing.  This fix will remove the additional sync(cpuid) before RDTSC on
Intel platforms..

Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

parent 97a4d003

include/asm-x86_64/timex.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -33,7 +33,7 @@ static __always_inline cycles_t get_cycles_sync(void)
		unsigned eax;
		/* Don't do an additional sync on CPUs where we know
		RDTSC is already synchronous. */
		alternative_io(ASM_NOP2, "cpuid", X86_FEATURE_SYNC_RDTSC,
		alternative_io("cpuid", ASM_NOP2, X86_FEATURE_SYNC_RDTSC,
		"=a" (eax), "0" (1) : "ebx","ecx","edx","memory");
		rdtscll(ret);
		return ret;