What does Xen / 'xm info' report on such a host ?
nr_cpus : 48 nr_nodes : 1 sockets_per_node : 4 cores_per_socket : 12 threads_per_core : 1 node_to_cpu : node0:0-47
Hmm, this was for the default case when NUMA is turned off in hypervisor. After setting numa=on on xen command line, the result is a bit different: nr_cpus : 48 nr_nodes : 8 sockets_per_node : 0 cores_per_socket : 12 threads_per_core : 1 node_to_cpu : node0:0-5 node1:6-11 node2:12-17 node3:18-23 node4:24-29 node5:30-35 node6:36-41 node7:42-47 sockets_per_node is reported to be zero. Jirka