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Re: [Xen-devel] Xen cpufreq support status: how to notify hypervisor of

To: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Subject: Re: [Xen-devel] Xen cpufreq support status: how to notify hypervisor of frequency change?
From: "Matt T. Yourst" <yourst@xxxxxxxxxx>
Date: Wed, 12 Apr 2006 22:31:17 -0400
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On Wednesday 12 April 2006 01:47 am, you wrote:
> local_time_calibration() won't really do the right thing. It will
> calibrate for the observed TSC rate over the last few seconds, most of
> which will have passed at the old TSC rate. The simplest fix would
> simply be to multiply the calculated TSC scale factor by
> new_mhz/old_mhz.

Doesn't set_time_scale() do exactly this by directly using the supplied 
ticks_per_sec value? Why does it need to be scaled based on the old frequency 
when the values can just be recalculated?

I removed the call to local_time_calibration() and it still works just fine, 
so it looks like set_time_scale() overrides the other settings anyway.

I'm still having a strange issue (only in X sessions it appears) where the key 
repeat rate and response time gets very slow after a frequency shift. 
Everything else responds normally except for the keyboard, and that problem 
goes away after a minute or two. Any idea what's going on?

- Matt

 Matt T. Yourst               yourst@xxxxxxxxxxxxxxxxx
 Binghamton University, Department of Computer Science

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