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[Xen-devel] Dom0 Hang for large VCPU counts > PCPU

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Subject: [Xen-devel] Dom0 Hang for large VCPU counts > PCPU
From: "Zulauf, John" <john.zulauf@xxxxxxxxx>
Date: Wed, 24 Jan 2007 10:56:45 -0800
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Thread-topic: Dom0 Hang for large VCPU counts > PCPU

We have been experimenting with large VCPU counts >> PCPU and have succeeded in hanging Dom0 in or during /sbin/loader.

 

Using xen-3.0.4-testing with an HVM booting the FC6 DVD on a Core2 Duo (i.e. 2 PCPU) on a 965 chipset

 

VCPU=17 – works

VCPU=20 – works (takes a very long time)

VCPU=24 – lockup (whole machine, yes I mean Dom0)

VCPU=31 – same

VCPU=32 – same

 

We’ve noted in the Xen l-apic code a hard 32 CPU limit (a uint32 used as an l-apic (vcpu?) bitmask), but this looks to be unrelated.

 

John Zulauf

Intel Corporation

 

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