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Re: [Xen-devel] CPU enumeration in Xen

On 22/8/07 14:48, "Daniel P. Berrange" <berrange@xxxxxxxxxx> wrote:

>> To my knowledge the enumeration order is determined by the order we find
>> CPUs in the BIOS tables, and can hence vary across different systems, and
>> even across BIOS upgrades.
> The HV may enumerate CPUs in the same way as Linux baremetal, but Dom0 sees
> VCPUs not physical CPUs. So /proc/cpuinfo in Dom0 will bear little resemblance
> to the same file on a bare metal machine. You'd need to compare the HV's view
> of physical CPUs to the Linux bare metal view, which isn't something you can
> do  by merely comparing /proc/cpuinfo AFAICT.

Oh yes, I missed this stunningly obvious point. :-)

If you want to tie dom0 VCPUs 1:1 with physical CPUs then you can put
dom0_vcpus_pin on your Xen command line.

To see how Xen enumerates the CPUs: look at 'xm dmesg', or look at Xen boot
output, to see APIC IDs of processors as they are booted.

 -- Keir

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