Re: [PATCH] 2.6.9-rc1 Ia64 build broken due to HPET

From: Christoph Lameter <clameter_at_sgi.com>
Date: 2004-09-14 08:50:33
On Mon, 13 Sep 2004, Alex Williamson wrote:

> > Well. This means that the resolution is broken for any clock > 1GHZ.
>    Yep, and the patch below at least fixes that much:

I checked that only the resolution is broken (unless the interpolator
shift is zero!). So the interpolators should now work fine at >1Ghz.

> > register_time_interpolator allows a later registration of a time
> > interpolator. The question though is: Will it win against the one
> > already installed. It may win if you specify a smaller drift than the ITC
> > interpolator. Gotta look at that.
>
>    Yes, it does win, so apparently the drift is smaller (I only put in
> enough printks so see that it won).  But the HPET interpolator is still
> coming in after init_posix_timers(), so the monotonic and realtime
> resolution isn't going to be updated to match the new timer without an
> additional hook in there.  Thanks,

Hmm... So if it wins and the posix time system is already up when
register time_interpolator is called then we need to redo
the posix timer setup or meddle with CLOCK_REALTIME and CLOCK_MONOTONIC
accuracy? Uggh....
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Received on Mon Sep 13 19:05:02 2004

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