On 10/17/2012 03:06 PM, Dusty Mabe wrote: > Hi, > > Would it be possible to augment the output produced in virsh > capabilities to also provide the hyperthreaded sibling of a processor? > For example the information would look something like: > > > <topology> > > <cells num='2'> > <cell id='0'> > <cpus num='8'> > <cpu id='1' sibling='9'/> Indeed, that sounds useful, and it is strictly additive so there is no technical reason preventing that addition. > I notice that you guys are actually using some of the numactl stuff > (numa.h) to query for the cpus on a given node and I have combed > through that code to see if it provided any info about hyperthreaded > siblings but from what I can tell it does not. I have tinkered around > with the hwloc libraries (http://www.open-mpi.org/projects/hwloc/) and > have written a short program to print out each logical cpu and its > hyperthreaded sibling (see attached) We haven't used hwloc before, but if that is the only way to get at the sibling information, it sounds like it might be a reasonable additional requirement for libvirt. On Fedora 17, I see: hwloc x86_64 1.4.1-2.fc17 updates 1.1 M hwloc-devel x86_64 1.4.1-2.fc17 updates 150 k so it looks like -lhwloc is currently bundled alongside the hwloc command line executable; the library itself is decently small: -rwxr-xr-x. 1 root root 163168 Apr 18 16:27 /usr/lib64/libhwloc.so.5.0.1 so I wonder if Fedora packaging should split that up so we only drag in the library instead of the whole command line utility. But that's a concern for Fedora, not this list. > Would you guys ever consider adding something like this? I would be > willing to help create a patch if I had some guidance. Absolutely! It sounds like there's several major places to touch to add this in: configure.ac - check for presence of hwloc libvirt.spec.in - require hwloc on new-enough Fedora docs - document the new XML docs/schemas - accept the new XML during RNG validation src/nodeinfo.c - use the new library, when availalble, to get at the new information tests - add a new xml file that demonstrates the RNG changes accept the new XML You may find it helpful to read http://libvirt.org/hacking.html -- Eric Blake eblake@xxxxxxxxxx +1-919-301-3266 Libvirt virtualization library http://libvirt.org
Attachment:
signature.asc
Description: OpenPGP digital signature
-- libvir-list mailing list libvir-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/libvir-list