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Subject: RE: Override timer interrupt
Date: Mon, 15 Oct 2007 16:50:53 -0500
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From: "Rune Torgersen" <runet@innovsys.com>
To: <benh@kernel.crashing.org>
Cc: linuxppc-dev@ozlabs.org, linuxppc-embedded@ozlabs.org
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> From: Benjamin Herrenschmidt>=20
> > The TB register is only ued for offsets from the last=20
> jiffie, not as a
> > continous offset, so then it works out pretty good.
>
> The date is derived from the absolute TB value though...

Huh? Not in 2.6.18/arch/ppc at least, unless I'm completely
misundrstanding the code.
ppc/powerpc seems to be using clocksource_jiffies as the clock source,
and teh gettimeofday gets xtime + a offset from last jiffie, and xtime
is updated with a fixed amount per tick.

Things have changed a lot since I last delved deep into this to try to
ge an accurate freerunning clock (2.6.12).