Features/Virtx2apic

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(move to 100% per FESCo ticket)
(Bump to 100, indicate virt-* should enable this automatically)
 
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* Targeted release: [[Releases/13 | Fedora 13]]  
 
* Targeted release: [[Releases/13 | Fedora 13]]  
 
* Last updated: 2010-04-06
 
* Last updated: 2010-04-06
* Percentage of completion: 190%
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* Percentage of completion: 100%
  
 
== Detailed Description ==
 
== Detailed Description ==
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== How To Test ==
 
== How To Test ==
* Run a Fedora 13 guest on a Fedora 13 host, with x2apic enabled.
+
* Run a Fedora 13 guest on a Fedora 13 host, with x2apic enabled. Installs via virt-install and virt-manager should enable this automatically.
 
* Verify that x2apic is present in /proc/cpuinfo.
 
* Verify that x2apic is present in /proc/cpuinfo.
 
* Verify dmesg contains "Enabling x2apic".
 
* Verify dmesg contains "Enabling x2apic".

Latest revision as of 22:14, 6 April 2010

Contents

[edit] Virt x2apic

[edit] Summary

x2apic is an x86 feature that improves performance, especially on large systems. Virt x2apic is a port of this feature for KVM, improving guest performance, especially for guests with many virtual processors.

[edit] Owner

[edit] Current status

  • Targeted release: Fedora 13
  • Last updated: 2010-04-06
  • Percentage of completion: 100%

[edit] Detailed Description

x2apic improves guest performance by reducing the overhead of APIC access, which is used to program timers and for issuing inter-processor interrupts. By exposing x2apic to guests, and by enabling the guest to utilize x2apic, we improve guest performance.

[edit] Benefit to Fedora

Fedora users will see improved guest performance and lower cpu utilization.

[edit] Scope

  • x2apic support is already present in the guest and host.
  • libvirt/virt-manager = ?

[edit] How To Test

  • Run a Fedora 13 guest on a Fedora 13 host, with x2apic enabled. Installs via virt-install and virt-manager should enable this automatically.
  • Verify that x2apic is present in /proc/cpuinfo.
  • Verify dmesg contains "Enabling x2apic".
  • For a bonus, measure the overhead of an IPI with and without x2apic.

[edit] User Experience

User experience is unchanged except for improved performance.

[edit] Dependencies

  • kernel
  • qemu-kvm
  • libvirt
  • virt-manager

[edit] Contingency Plan

  • Since this is a transparent feature, no contingency plan is necessary.

[edit] Documentation

  • FIXME: link to upstream docs?

[edit] Release Notes

  • Fedora 13 virtualization supports x2apic in both the host and guest roles.

[edit] Comments and Discussion