Commit 6c132b5f authored by john stultz's avatar john stultz Committed by Linus Torvalds

[PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs

This should resolve the issue seen in bugme bug #5105, where it is assumed
that dualcore x86_64 systems have synced TSCs.  This is not the case, and
alternate timesources should be used instead.

For more details, see:

Andi's earlier concerns that the TSCs should be synced on dualcore systems
have been resolved by confirmation from AMD folks that they can be
Acked-by: default avatarAndi Kleen <>
Signed-off-by: default avatarAndrew Morton <>
Signed-off-by: default avatarLinus Torvalds <>
parent a9d014af
......@@ -959,9 +959,6 @@ static __init int unsynchronized_tsc(void)
are handled in the OEM check above. */
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL)
return 0;
/* All in a single socket - should be synchronized */
if (cpus_weight(cpu_core_map[0]) == num_online_cpus())
return 0;
/* Assume multi socket systems are not synchronized */
return num_online_cpus() > 1;
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