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Re: [Xen-devel] Performance difference between Xen versions

On Mon, May 02, 2011 at 10:52:45AM -0700, John Weekes wrote:
> On 5/2/2011 12:23 AM, Jan Beulich wrote:
> >Correct. I generally found the default threshold of the ondemand
> >governor nor very suitable for optimal performance of short lived
> >jobs, and boot all of my systems with "cpufreq=xen:ondemand,threshold=20".
> These pm comments made me wonder about turbo mode, which I've never
> seen working, and the fact that xenpm doesn't work for me either
> (for instance, trying to turn on turbo with it causes Xen to
> freeze). So, I started digging a bit.
> I'm testing with 4.1. I started by setting my line to include the
> one that you gave as an example, but adding ",verbose=1" to the end
> in order to see more output. Strangely, I didn't see any, and turbo
> mode was still not being set (and frequencies weren't changing).
> I added some further debug code and found that cpufreq_add_cpu was
> aborting because of its "if (!processor_pminfo[cpu])" check at the
> beginning. I can't find where processor_pminfo[cpu] would be set
> anywhere but in the set_px_pminfo hypercall (via copying), and I
> can't find a caller of that function anywhere in the Xen source or
> 2.6.32-stable kernel source. I do see it mentioned in the old

Oh? I think git commit a3ca5a20ec9d5c4917271021d49768961e7a8421
Author: Yu Ke <ke.yu@xxxxxxxxx>
Date:   Thu Apr 28 09:50:55 2011 -0400

    xen/acpi: add xen acpi processor driver
    Xen hypervisor need parsed acpi processor info for CPU Cx/Px power 
    so this patch introduces xen acpi processor driver to parse the acpi info,
    and notify the hypervisor upon receiving the info.
    This patch has two components:
     - driver/acpi/processor_xen.c: implement the xen acpi processor driver
     - drivers/xen/acpi_processor.c: provide the interface to notify Xen 
adds it in the 2.6.32 tree?

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