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    SubjectRe: gettimeofday order of magnitude slower with pmtimer, which is default
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    On Tue, 21 Mar 2006 01:59 pm, OGAWA Hirofumi wrote:
    > Yes. However, if machines uses buggy chip, I guessed TSC/PIT would be
    > more proper as time source.

    Oh yes but there has been an epidemic of timer problems (fast/slow, lost ticks
    etc) lately meaning the pm timer is being relied upon more and more.

    > But probably you are right, timer_pit.c
    > seems more slow usually (it uses many I/O port).
    >
    > I'll remove unlikely(), and also will remove "Use other timer source"
    > from warning.

    Suggesting another timer source is ok in the warning I believe given massive
    amounts of wasted cpu.

    > BTW, this patch is still quick hack.

    Understood. Perhaps having an indirect function call set to either
    good_pmtmr() or bad_pmtmr() after checking would be preferable to a variable
    that is checked on each function call despite never changing.

    > At least, we would need to check the ICH4 which says in comment.
    > However, I couldn't find the PM-Timer Errata in ICH4 spec update.
    >
    > Do you/anyone know about a ICH4 error?

    Not personally but my ICH4 pm timer seems to work very well whereas Andi's
    apparently similar chipset exhibits terrible problems.

    Cheers,
    Con
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