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    SubjectRe: [PATCH] scheduler: fix x86 regression in native_sched_clock
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    On Saturday 08 December 2007 03:48, Nick Piggin wrote:
    > On Friday 07 December 2007 22:17, Ingo Molnar wrote:
    > > * Nick Piggin <nickpiggin@yahoo.com.au> wrote:
    > > > > ah, printk_clock() still uses sched_clock(), not jiffies. So it's
    > > > > not the jiffies counter that goes back and forth, it's sched_clock()
    > > > > - so this is a printk timestamps anomaly, not related to jiffies. I
    > > > > thought we have fixed this bug in the printk code already:
    > > > > sched_clock() is a 'raw' interface that should not be used directly
    > > > > - the proper interface is cpu_clock(cpu).
    > > >
    > > > It's a single CPU box, so sched_clock() jumping would still be
    > > > problematic, no?
    > >
    > > sched_clock() is an internal API - the non-jumping API to be used by
    > > printk is cpu_clock().
    >
    > You know why sched_clock jumps when the TSC frequency changes, right?

    Ah, hmm, I don't know why I wrote that :)

    I guess your patch is fairly complex but it should work if the plan
    is to convert all sched_clock users to use cpu_clock eg like lockdep
    as well.

    So it looks good to me, thanks for fixing this.


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