Public bug reported: The 3.0 Linux kernel used in Ubuntu 11.04 and 11.10 is lacking a rather key set of patches in which inform the Xen hypervisor about the power management (specifically cpufreq scaling) properties of the processors in the system. Without these patches, Xen will not make use of the highest performing CPU frequencies. These patches are in the process of being upstreamed to Linux mainline at version 3.3, but are already readily available and reasonably easy to apply to a 3.0 onwards kernel. You can find them at:
git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen.git devel/acpi- cpufreq.v4 Because of the rather large performance penalty without these patches, I propose that this backport be included in the Ubuntu 3.2 kernel for Precise. Since this patch series can be applied to 3.0, it would be nice to include this in the 3.0 kernel for Oneiric as well. Please see the following blog post for a more detailed description of the issue: http://blog.xen.org/index.php/2011/11/29/baremetal-vs-xen-vs-kvm-redux/ ** Affects: linux (Ubuntu) Importance: Undecided Status: New -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/898112 Title: Xen performance issue: backport acpi-cpufreq.v4 branch to 3.2 kernel for Precise To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/898112/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
