Features/Virtx2apic

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(Virt x2apic)
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== Owner ==
 
== Owner ==
 
* Name: [[User:avik| Avi Kivity]]
 
* Name: [[User:avik| Avi Kivity]]
 
 
* Email: <avi@redhat.com>
 
* Email: <avi@redhat.com>
  
 
== Current status ==
 
== Current status ==
* Targeted release: [[Releases/13]]  
+
* Targeted release: [[Releases/13 | Fedora 13]]  
 
* Last updated: 2010-01-26
 
* Last updated: 2010-01-26
 
* Percentage of completion: 90%
 
* Percentage of completion: 90%
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== Scope ==
 
== Scope ==
x2apic support is already present in the guest and host.
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* x2apic support is already present in the guest and host.
libvirt/virt-manager = ?
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* libvirt/virt-manager = ?
  
 
== How To Test ==
 
== How To Test ==
Run a Fedora 13 guest on a Fedora 13 host, with x2apic enabled.
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* Run a Fedora 13 guest on a Fedora 13 host, with x2apic enabled.
 
+
* 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".
+
* For a bonus, measure the overhead of an IPI with and without x2apic.
 
+
For a bonus, measure the overhead of an IPI with and without x2apic.
+
  
 
== User Experience ==
 
== User Experience ==
 
User experience is unchanged except for improved performance.
 
User experience is unchanged except for improved performance.
 
  
 
== Dependencies ==
 
== Dependencies ==
kernel
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* kernel
qemu-kvm
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* qemu-kvm
libvirt
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* libvirt
virt-manager
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* virt-manager
  
 
== Contingency Plan ==
 
== Contingency Plan ==
Since this is a transparent feature, no contingency plan is necessary.
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* Since this is a transparent feature, no contingency plan is necessary.
  
 
== Documentation ==
 
== Documentation ==
* Nope.
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* '''FIXME''': link to upstream docs?
  
 
== Release Notes ==
 
== Release Notes ==
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== Comments and Discussion ==
 
== Comments and Discussion ==
 
* See [[Talk:Features/Virtx2apic]]
 
* See [[Talk:Features/Virtx2apic]]
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[[Category:FeatureReadyForFesco]]
  
 
[[Category:Virtualization|Virtx2apic]]
 
[[Category:Virtualization|Virtx2apic]]
[[Category:FeatureReadyForWrangler]]
 
 
[[Category:F13_Virt_Features|Virtx2apic]]
 
[[Category:F13_Virt_Features|Virtx2apic]]
<!-- When your feature page is completed and ready for review -->
 
<!-- remove Category:FeaturePageIncomplete and change it to Category:FeatureReadyForWrangler -->
 
<!-- After review, the feature wrangler will move your page to Category:FeatureReadyForFesco... if it still needs more work it will move back to Category:FeaturePageIncomplete-->
 
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Revision as of 05:04, 29 January 2010

Contents

Virt x2apic

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.

Owner

Current status

  • Targeted release: Fedora 13
  • Last updated: 2010-01-26
  • Percentage of completion: 90%

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.

Benefit to Fedora

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

Scope

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

How To Test

  • Run a Fedora 13 guest on a Fedora 13 host, with x2apic enabled.
  • 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.

User Experience

User experience is unchanged except for improved performance.

Dependencies

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

Contingency Plan

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

Documentation

  • FIXME: link to upstream docs?

Release Notes

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

Comments and Discussion