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

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Commit c818a18146 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>
This commit is contained in:
Siddha, Suresh B
2006-04-11 12:54:42 +02:00
committed by Linus Torvalds
parent 97a4d00388
commit e4cff6ac78
1 changed files with 1 additions and 1 deletions
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2
include/asm-x86_64/timex.h
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@@ -33,7 +33,7 @@ static __always_inline cycles_t get_cycles_sync(void)
unsigned eax; unsigned eax;
/* Don't do an additional sync on CPUs where we know /* Don't do an additional sync on CPUs where we know
RDTSC is already synchronous. */ 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"); "=a" (eax), "0" (1) : "ebx","ecx","edx","memory");
rdtscll(ret); rdtscll(ret);
return ret; return ret;