Re: RES: [Xen-users] XCP WinPV drivers

[John Buchanan <John.Buchanan@xxxxxxxxxxxxxxxxxx>]

In that case their cpu doesn't support HT.  If I recall Intel reintroduced that (server side) with the 5500 family.

As to your thoughts I've pondered the same.  My company produces a student information system, and for most of our customers my department manages the servers on which the SIS is hosted.  A few who are "self-hosted" have virtualized the web servers and in each case where they've had performance issues the common factor seems to be either "over subscribing" the host, or similarly, under-provisioning the individual VM's.  The reason I mention this is I'm currently working with a self-hosted customer running Vmware Vsphere Esxi on 4 HP blades, each with 2 X5570 processors.  Our recommendation had been to provision each web server with the equiavalent of 1-2 cores, they allocated 1 Vcpu.  The X5570 is hyperthreaded, and now that I find that they're seeing average cpu utilization (of the VM's) in the 50-70% range, I go back to our recommendation. While it may be splitting hairs, IMHO by allocating only 1 Vcpu they only allocated the equivalent of 1/2 of one core.

From: Eduardo Bragatto <eduardo@xxxxxxxxxxxx>
Date: Mon, 28 Mar 2011 15:14:54 -0500
To: xen-users <xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: Re: RES: [Xen-users] XCP WinPV drivers

On Mar 28, 2011, at 3:48 PM, Eduardo Kanashiro (eduardo.kanashiro) wrote:

We have a similar environment running Windows 2008 R2 VM, and our host processor are Xeon E5402 quad core without HT neither turbo core, but I have experienced the same issue after install the latest versions of Xentool.

Is there any special reason for not using HT with Xen? I never had a problem, but I always ask myself if I'm giving just half CPU when I assign 1 vCPU to a VM on a system which has HT enabled.

Regards,

Eduardo.

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