Xen performance kernel patches backported to 3.2 for Precise

Mike McClurg mike.mcclurg at citrix.com
Wed Nov 30 11:38:22 UTC 2011

Hello Kernel Team,

I have just created bug report #898112 [1]. This bug is related to a
kernel issue which negatively affects Xen performance on Ubuntu 11.04
and later. This issue is caused by the kernel incorrectly reporting the
cpufreq capabilities of the CPU to Xen, which prevents the hypervisor
from setting the CPU to the maximum frequency scaling.

A blog post describing the bug in detail can be found here [2]. The
patch series, which has been backported to 3.2 (and I believe 3.0 as
well) can be found here [3].

I ask the kernel team to consider including the 3.2 backport of this
branch in the Precise kernel, and possibly the Oneiric kernel as well,
if this is possible. Please feel free to contact me or Konrad (the patch
author) with any questions. Thanks,


[1] https://bugs.launchpad.net/ubuntu/+source/linux/+bug/898112
[2] http://blog.xen.org/index.php/2011/11/29/baremetal-vs-xen-vs-kvm-redux/

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