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    SubjectRe: [PATCH 3/4] new timeofday x86-64 arch specific changes (v. B1)
    On Thursday 02 June 2005 19:20, john stultz wrote:
    > Could you see if the slowness you're feeling is correlated to the
    > acpi_pm timesource?

    Speaking of which, the below code from arch/i386/timer_pm.c looks particularly
    more taxing to me - 3 times read from ioport in a loop - not sure how many
    time that executes.

    static inline u32 read_pmtmr(void)
    u32 v1=0,v2=0,v3=0;
    /* It has been reported that because of various broken
    * chipsets (ICH4, PIIX4 and PIIX4E) where the ACPI PM time
    * source is not latched, so you must read it multiple
    * times to insure a safe value is read.
    do {
    v1 = inl(pmtmr_ioport);
    v2 = inl(pmtmr_ioport);
    v3 = inl(pmtmr_ioport);
    } while ((v1 > v2 && v1 < v3) || (v2 > v3 && v2 < v1)
    || (v3 > v1 && v3 < v2));

    Shouldn't that loop be limited to the broken chipsets - why would correct
    people with correctly working chipsets carry this extra burden? (Or is it

    Because we don't think about future generations, they will never forget us.
    -- Henrik Tikkanen
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