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    SubjectRe: [RFC][PATCH] new timeofday core subsystem (v. A2)
    Minor spelling fix, and a question.

    john stultz wrote:
    > linux-2.6.11-rc2_timeofday-core_A2.patch
    > ========================================
    > diff -Nru a/drivers/Makefile b/drivers/Makefile
    > --- a/drivers/Makefile 2005-01-24 13:30:06 -08:00
    > +++ b/drivers/Makefile 2005-01-24 13:30:06 -08:00
    ...

    > + * all systems. It has the same course resolution as
    should be "coarse"

    Do you replace get_cmos_time() - it doesn't look like it.

    You use it in your patch here...

    > diff -Nru a/arch/i386/kernel/time.c b/arch/i386/kernel/time.c
    > --- a/arch/i386/kernel/time.c 2005-01-24 13:33:59 -08:00
    > +++ b/arch/i386/kernel/time.c 2005-01-24 13:33:59 -08:00
    ...

    > +/* arch specific timeofday hooks */
    > +nsec_t read_persistent_clock(void)
    > +{
    > + return (nsec_t)get_cmos_time() * NSEC_PER_SEC;
    > +}
    > +

    I didn't scan for all uses of read_persistent_clock, but
    in my experience get_cmos_time() has a latency of up to
    1 second on x86 because it synchronizes with the rollover
    of the RTC seconds.

    This comment in timeofday.c:timeofday_suspend_hook
    worries me:

    > + /* First off, save suspend start time
    > + * then quickly read the time source.
    > + * These two calls hopefully occur quickly
    > + * because the difference will accumulate as
    > + * time drift on resume.
    > + */
    > + suspend_start = read_persistent_clock();

    Do you know if the sync problem is an issue here?

    =============================
    Tim Bird
    Architecture Group Chair, CE Linux Forum
    Senior Staff Engineer, Sony Electronics
    =============================
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