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Re: [Xen-devel] Frequency scaling not working

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Subject: Re: [Xen-devel] Frequency scaling not working
From: Mark Williamson <mark.williamson@xxxxxxxxxxxx>
Date: Tue, 24 Apr 2007 17:31:43 +0100
Cc: sriram govindan <sriram_ite@xxxxxxxxxxx>
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> I installed the latest version of xen (3.0.4_1). I used userspace governor
> to change frequency of my xeon dual processor SMT. The driver used is
> p4-clockmod.
> Changes to the frequency (through the /sys interface) is not getting
> reflected to the hardware. From previous posts, i understand that rdmsr and
> wrmsr has to be replaced with dom0_msr operations. Even after doing the
> modifications, still the frequency is not getting changed and the domain0
> hypercall is returning a negative value when reads and writes are made to
> the dom0_msr.

I'm not sure frequency scaling is supported by 3.0.4, although I expect it 
will be one day.

> Also, In xen SMT seems to have some problems. cpumask (affected cpus) does
> not seem to include the hyperthread.

I'm not entirely sure I understand the question here...  The hyperthreads 
should be enumerated as separate processors and Just Work.  What behaviour 
are you seeing?


Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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