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    SubjectRe: [PATCH] tsc-disable_B9
    On Fri, 2002-08-09 at 02:17, Alan Cox wrote:
    > On Fri, 2002-08-09 at 03:30, john stultz wrote:
    > > Not sure I followed that, do you mean per-cpu TSC management for
    > > gettimeofday?
    > We have some x86 setups where people plug say a 300MHhz and a 450MHz
    > celeron into the same board. This works because they are same FSB,
    > different multiplier (works and intel certify being two different
    > things)

    Oh yes, with the old NUMAQ hardware here, one can mix nodes of different
    speed cpus. Once I get a chance, I'm going to begin working on this
    issue for 2.5. My plan right now is to keep per-cpu last_tsc_low and
    fast_gettimeoffset_quotient values, then round robin the timer

    > Needless to say tsc does not work well on such boxes. Thats why I don't
    > trust the tsc at all in such cases. Since you'll have the nice cyclone
    > timer for the Summit it seems best not to trust it, and on the summit to
    > use the cyclone for udelay as well ?
    > I agree dodgy_tsc needs to change name. Perhaps we actually want
    > int tsc = select_tsc();
    > switch(tsc)
    > {
    > case TSC_CYCLONE:
    > case TSC_PROCESSOR:
    > case TSC_NONE:
    > ..
    > }

    Sounds good. I'll re-work my patch and resubmit.


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