Re: [PATCH v3 1/4] Add correlated clocksource deriving system time from an auxiliary clocksource

From: Peter Zijlstra
Date: Fri Sep 04 2015 - 11:10:34 EST

On Fri, Sep 04, 2015 at 03:02:19PM +0200, Thomas Gleixner wrote:
> > For example, supply the ART value as an argument and, in the case of
> > the realtime clock, keep a short history of clock changes. It would
> It's not only clock realtime which is affected by those.
> > fail in cases where there are a lot of calls to adjtimex(),
> That has nothing to do with lots of adjtimex calls. The kernel does a
> slow correction of the conversion values itself to avoid time jumping
> around.

I think what they're getting at is asking if there's a rate limit to
time adjustments, without that, saving the last n transition points will
still not cover any given length of history.

So what I think they're looking for; is given an upper bound on the DSP
delaying its data, come up with a fixed minimal amount of transitions
points we must store to cover the history.

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