libvirt users - Sep 2012 - picking a NUMA cell for pinning using virsh freecell

Hi

I'd want to pin the vcpu of a guest to a pcpu.

the docs clearly say
https://access.redhat.com/knowledge/docs/en-US/Red_Hat_Enterprise_Linux/6/html/Virtualization_Administration_Guide/ch09s04.html

"Locking a guest to a particular NUMA node offers no benefit if that node 
does not have sufficient free memory for that guest. libvirt stores 
information on the free memory available on each node. Use the virsh 
freecell --all command to display the free memory on all NUMA nodes "

I have tried to look at what freecell returns and heuristically its total 
across cells looks roughly the same value returned by the 'free' command
but without discounting buffers and cache.
While free is able to show the value when buffers/cache are taken into 
account, free is not able to apportion that to NUMA cells.

So is it really a valid strategy to choose the NUMA cell for pinning vcpus 
looking at  virsh freecell
or ideally we'd need those values adjusted with buffers+cache ?
And if so how could one do that ?

--------------------------------------------------
regards,
Edoardo Comar
IBM SWG UK - Hursley JTC
ecomar at uk.ibm.com
Tel +44 (0)1962 81 5576 (external)  245576  (internal) 
IBM UK Ltd, Hursley, SO21 2JN

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