[lkml]   [2002]   [Dec]   [16]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: Intel P6 vs P7 system call performance

    On Tue, 17 Dec 2002, Dave Jones wrote:
    > I'm sure I recall seeing errata on at least 1 CPU re sysenter.
    > If we do decide to go this route, we'll need to blacklist ones
    > with any really icky problems.

    The errata is something like "all P6's report SEP, but it doesn't
    actually _work_ on anything before the third stepping".

    However, that should _not_ be handled by magic sysenter-specific code.
    That's what the per-vendor cpu feature fixups are there for, so that these
    kinds of bugs get fixed in _one_ place (initialization) and not in all the
    users of the feature flags.

    In fact, we already have that code in the proper place, namely

    /* SEP CPUID bug: Pentium Pro reports SEP but doesn't have it */
    if ( c->x86 == 6 && c->x86_model < 3 && c->x86_mask < 3 )
    clear_bit(X86_FEATURE_SEP, c->x86_capability);

    so the stuff I sent out should work on everything.

    (Modulo the missing syscall page I already mentioned and potential bugs
    in the code itself, of course ;)


    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    More majordomo info at
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:31    [W:0.022 / U:34.188 seconds]
    ©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site