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    SubjectRe: [PATCH] x86-64: Fix bad assumption that dualcore cpus have synced TSCs (resend)
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    Hi John.

    > This patch 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.
    >
    > Please consider for inclusion in your tree.

    Wouldn't it be a good idea to change the comment following
    the code you removed as well?

    Why have a comment saying "multi socket systems" if there is no
    distinction anymore?

    >
    > diff --git a/arch/x86_64/kernel/time.c b/arch/x86_64/kernel/time.c
    > --- a/arch/x86_64/kernel/time.c
    > +++ b/arch/x86_64/kernel/time.c
    > @@ -959,9 +959,6 @@ static __init int unsynchronized_tsc(voi
    > 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;

    // Stefan
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