David Hildenbrand <da...@redhat.com> writes: > On 11.10.22 08:03, Markus Armbruster wrote: >> David Hildenbrand <da...@redhat.com> writes: >> >>> Let's make it easier to pin threads created via a ThreadContext to >>> all CPUs currently belonging to a given set of NUMA nodes -- which is the >>> common case. >>> >>> "node-affinity" is simply a shortcut for setting "cpu-affinity" manually >>> to the list of CPUs belonging to the set of nodes. This property can only >>> be written. >>> >>> A simple QEMU example to set the CPU affinity to Node 1 on a system with >>> two NUMA nodes, 24 CPUs each: >>> qemu-system-x86_64 -S \ >>> -object thread-context,id=tc1,node-affinity=1 >>> >>> And we can query the cpu-affinity via HMP/QMP: >>> (qemu) qom-get tc1 cpu-affinity >>> [ >>> 1, >>> 3, >>> 5, >>> 7, >>> 9, >>> 11, >>> 13, >>> 15, >>> 17, >>> 19, >>> 21, >>> 23, >>> 25, >>> 27, >>> 29, >>> 31, >>> 33, >>> 35, >>> 37, >>> 39, >>> 41, >>> 43, >>> 45, >>> 47 >>> ] >> >> Double-checking my understanding: on this system, the even CPUs belong >> to NUMA node 0, and the odd ones to node 1. Setting node-affinity=1 is >> therefore sugar for setting cpu-affinity to the set of even CPUs. >> Correct? > > Yes! > > # lscpu > ... > NUMA: > NUMA node(s): 2 > NUMA node0 CPU(s): > 0,2,4,6,8,10,12,14,16,18,20,22,24,26,28,30,32,34,36,38,40,42,44,46 > NUMA node1 CPU(s): > 1,3,5,7,9,11,13,15,17,19,21,23,25,27,29,31,33,35,37,39,41,43,45,47
Thanks! >>> We cannot query the node-affinity: >>> (qemu) qom-get tc1 node-affinity >>> Error: Insufficient permission to perform this operation >> >> The error message is somewhat misleading. "Insufficient permission" >> suggests this could work if I had more "permission". Not the case. The >> message comes from object_property_get(), i.e. it's not this patch's >> fault. I'll post a patch to improve it. > > I agree, thanks! QAPI schema Acked-by: Markus Armbruster <arm...@redhat.com>
