Re: [libvirt] virsh nodeinfo CPU detection questions

On 01/29/2013 02:55 PM, Doug Goldstein wrote: > > On Tue, Jan 29, 2013 at 9:52 AM, Scott Sullivan<ssullivan(a)liquidweb.com> > wrote: > >> >> I have a machine with four AMD Opteron(TM) 6272 processors: >> >> >> http://www.amd.com/us/products/server/processors/6000-series-platform/620... >> >> I use 'virsh nodeinfo' to determine the amount of physical CPUs, and CPU >> cores. What values should I be looking at in the output of nodeinfo to >> determine this? With 1.X libvirts the output values have changed from >> 0.9.4: >> >> 0.9.4: >> [root@host ~]# virsh nodeinfo >> CPU model: x86_64 >> CPU(s): 64 >> CPU frequency: 2099 MHz >> CPU socket(s): 4 >> Core(s) per socket: 8 >> Thread(s) per core: 2 >> NUMA cell(s): 1 >> Memory size: 24713980 kB >> [root@host28 ~]# >> >> 1.0.1: >> [root@host ~]# virsh nodeinfo >> CPU model: x86_64 >> CPU(s): 64 >> CPU frequency: 2099 MHz >> CPU socket(s): 1 >> Core(s) per socket: 8 >> Thread(s) per core: 2 >> NUMA cell(s): 4 >> Memory size: 24713980 KiB >> [root@host28 ~]# >> >> As you can see, the CPU socket and NUMA cells values have changed in >> these >> two versions, on the same machine. To get the physical CPU count, is it >> safe >> to assume this? >> >> Numa cell(s) X CPU Socket(s) == physical CPUs present >> >> However, I am not positive what formula I should use to determine the CPU >> core count. On this processor, it has 16 cores. Would that mean I can do >> this? >> >> Core(s) per socket X Thread(s) per core: == CPU cores >> >> Thanks in advance for clarifying. >> >> -- >> libvir-list mailing list >> libvir-list(a)redhat.com >> https://www.redhat.com/mailman/listinfo/libvir-list >> > > Scott, > > I've got the exact same CPUs (Dell PowerEdge R815). You'll find the > NUMA info is detected node info is detected incorrectly. Oddly we have > different data detected. What kernel are you running? > > with libvirt 1.0.1 > root@host ~ # virsh nodeinfo > CPU model: x86_64 > CPU(s): 64 > CPU frequency: 2100 MHz > CPU socket(s): 1 > Core(s) per socket: 64 > Thread(s) per core: 1 > NUMA cell(s): 1 > Memory size: 132013200 KiB > > virsh capabilities is a bit "smarter" but still not 100%. It sees 8 > NUMA nodes and puts the CPUs in the correct nodes but still detects > the CPU incorrectly. > > Doug, I'm running a RedHat kernel; 2.6.32-220.2.1.el6.x86_64 specifically. Thanks for the insight of your experiences, very interesting. I find the same that the NUMA info appears detected incorrectly for this processor.