[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:
http://bugzilla.kernel.org/show_bug.cgi?id=5105

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
unsynced.

Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 0 insertions, 3 deletions

diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
index 2373cb8b8625..703acde2a1a5 100644
--- a/arch/x86_64/kernel/time.c
+++ b/arch/x86_64/kernel/time.c
@@ -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;
 #endif
         /* Assume multi socket systems are not synchronized */
         return num_online_cpus() > 1;