Re: [libvirt] [PATCH 12/12] nodedev: Export NUMA node locality for PCI devices

On Thu, May 29, 2014 at 10:32:46AM +0200, Michal Privoznik wrote: > A PCI device can be associated with a specific NUMA node. Later, when > a guest is pinned to one NUMA node the PCI device can be assigned on > different NUMA node. This makes DMA transfers travel across nodes and > thus results in suboptimal performance. We should expose the NUMA node > locality for PCI devices so management applications can make better > decisions. > > Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; > --- > > Notes: > All the machines I have tried this on had only -1 in the > numa_node file. From the kernel sources it seems that this is the > default, so I'm not printing the <numa/> element into the XML in > this case. But I'd like to hear your opinion. Yes, I believe '-1' means that there is no NUMA locality info available for the device, so it makes sense to skip this.