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[Xen-users] CPU enumeration

To: "xen-users@xxxxxxxxxxxxxxxxxxx" <xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-users] CPU enumeration
From: John Buchanan <John.Buchanan@xxxxxxxxxxxxxxxxxx>
Date: Wed, 3 Nov 2010 13:37:45 -0500
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Is it possible to alter how XCP enumerates multi-core cpu’s such that a Vcpu represents a “socket”, rather than a “core”?  A server with dual quad core processors, no HT, presents each of the 8 cores as a Vcpu to the guest.  Windows Server 2008 R2 see’s each Vcpu as a unique “socket” and we are therefore coming up against licensing issues with Windows and more importantly SQL Server 2008 Standard Ed which is licensed for a maximum of 4 cpu’s (meaning 4 cores of a quad-core processor as a VM).  The issue is worsened on a system with HT because then the quad core processor is presented to the VM’s as having 8 Vcpu’s, and SQL Server 2008 will only use 4 of them, or half the actual cores in a given cpu.

When Windows Server 2008 R2 Standard edition is installed “bare metal” on the same dual-quad server it identifies the system as a dual processor with 8 total cores, and SQL Server then uses all 8 cores.

I understand that it is possible make some alterations using “xe vm-param-set uuid=<vm uuid> VCPUs-params:”.  But I’m not finding a way to present this two socket server as such to the guest, rather than an 8-socket system.

Running XCP 0.5.0 on a Dell PE2950 with dual E5410 Xeon processors.


John Buchanan
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