I cam up with this snippet of code so I could find the PCI devices closest to
where a process was running. This works fine on a NUMA node. However, on a
non-NUMA node, it appears that the HWLOC bridge is not connected to anything.
Therefore, I believe I just need to do something like
hwloc_get_obj_by_type(topology, HWLOC_OBJ_BRIDGE, 0) when running on a non-NUMA
node. Does that seem correct? Should I special case where I do not find a
HWLOC_OBJ_NODE object?
retval = hwloc_topology_init(&topology);
retval = hwloc_topology_set_flags(topology, flags);
retval = hwloc_topology_load(topology);
newset = hwloc_bitmap_alloc();
retval = hwloc_get_last_cpu_location(topology, newset, 0);
/* Get the object that contains the cpuset */
node = hwloc_get_first_largest_obj_inside_cpuset(topology, newset);
/* Climb up from that object until we find HWLOC_OBJ_NODE */
while (node->type != HWLOC_OBJ_NODE) {
node = node->parent;
}
/* Now look for the HWLOC_OBJ_BRIDGE. All PCI busses hanging off the
* node will have one of these */
bridge = hwloc_get_next_child(topology, node, NULL);
while (bridge != NULL && bridge->type != HWLOC_OBJ_BRIDGE) {
bridge = hwloc_get_next_child(topology, node, bridge);
}
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