On Fri, May 16, 2008 at 10:47:40PM +0100, Daniel P. Berrange wrote:
KVM added ability to get the thread ID for vCPUs via the monitor
(qemu) info cpus * CPU #0: pc=0x00000000000ffff0 thread_id=11463 CPU #1: pc=0x00000000fffffff0 thread_id=11464 CPU #2: pc=0x00000000fffffff0 thread_id=11465
With this we have enough information to be able to support vCPU pinning in the QEMU driver for KVM. For QEMU/KQEMU it is trivial, since they have a single thread.
The following patch implements CPU pinning and fetching of CPU affinity information. In this example I pin one of the 2 cpus in a guest: [...] This is implemented using sched_setaffinity/sched_getaffinity which are Linux specific. There doesn't appear to be a portable process affinity API in POSIX.
looks fine to me. I guess the main use will be for KVM which is Linux specific, so that should not be a big deal IMHO (if we could just make sure the code doesn't bomb at compile time on say Solaris).
If the KVM instance does not support the 'thread_id' data in 'info cpus', we simply print out a suitable error message. We detect the mapping at startup and cache it thereafter.
Hum, okay, seems that should work just fine even if one migrates or save/restore. Is the error reported each time one starts a new VM ? In any case looks fine, +1 Daniel -- Red Hat Virtualization group http://redhat.com/virtualization/ Daniel Veillard | virtualization library http://libvirt.org/ veillard@redhat.com | libxml GNOME XML XSLT toolkit http://xmlsoft.org/ http://veillard.com/ | Rpmfind RPM search engine http://rpmfind.net/