void *
hwloc_alloc_membind(hwloc_topology_t topology, size_t len, hwloc_const_cpuset_t set, hwloc_membind_policy_t policy, int flags)
{
hwloc_nodeset_t nodeset = hwloc_bitmap_alloc();
void *ret;
if (hwloc_fix_membind_cpuset(topology, nodeset, set)) {
if (flags & HWLOC_MEMBIND_STRICT)
ret = NULL;
else
ret = hwloc_alloc(topology, len);
} else
ret = hwloc_alloc_membind_nodeset(topology, len, nodeset, policy, flags);
hwloc_bitmap_free(nodeset);
return ret;
}
int main(void)
{
int depth;
unsigned i, n;
unsigned long size;
int levels;
char string[128];
int topodepth;
void *m;
hwloc_topology_t topology;
hwloc_cpuset_t cpuset;
hwloc_obj_t obj;
/* Allocate and initialize topology object. */
hwloc_topology_init(&topology);
/* ... Optionally, put detection configuration here to ignore
some objects types, define a synthetic topology, etc....
The default is to detect all the objects of the machine that
the caller is allowed to access. See Configure Topology
Detection. */
/* Perform the topology detection. */
hwloc_topology_load(topology);
/* Optionally, get some additional topology information
in case we need the topology depth later. */
topodepth = hwloc_topology_get_depth(topology);
/*****************************************************************
* First example:
* Walk the topology with an array style, from level 0 (always
* the system level) to the lowest level (always the proc level).
*****************************************************************/
for (depth = 0; depth < topodepth; depth++) {
printf("*** Objects at level %d\n", depth);
for (i = 0; i < hwloc_get_nbobjs_by_depth(topology, depth);
i++) {
hwloc_obj_type_snprintf(string, sizeof(string),
hwloc_get_obj_by_depth(topology, depth, i), 0);
printf("Index %u: %s\n", i, string);
}
}
/*****************************************************************
* Second example:
* Walk the topology with a tree style.
*****************************************************************/
printf("*** Printing overall tree\n");
print_children(topology, hwloc_get_root_obj(topology), 0);
/*****************************************************************
* Third example:
* Print the number of packages.
*****************************************************************/
depth = hwloc_get_type_depth(topology, HWLOC_OBJ_PACKAGE);
if (depth == HWLOC_TYPE_DEPTH_UNKNOWN) {
printf("*** The number of packages is unknown\n");
} else {
printf("*** %u package(s)\n",
hwloc_get_nbobjs_by_depth(topology, depth));
}
/*****************************************************************
* Fourth example:
* Compute the amount of cache that the first logical processor
* has above it.
*****************************************************************/
levels = 0;
size = 0;
for (obj = hwloc_get_obj_by_type(topology, HWLOC_OBJ_PU, 0);
obj;
obj = obj->parent)
if (obj->type == HWLOC_OBJ_CACHE) {
levels++;
size += obj->attr->cache.size;
}
printf("*** Logical processor 0 has %d caches totaling %luKB\n",
levels, size / 1024);
/*****************************************************************
* Fifth example:
* Bind to only one thread of the last core of the machine.
*
* First find out where cores are, or else smaller sets of CPUs if
* the OS doesn't have the notion of a "core".
*****************************************************************/
depth = hwloc_get_type_or_below_depth(topology, HWLOC_OBJ_CORE);
/* Get last core. */
obj = hwloc_get_obj_by_depth(topology, depth,
hwloc_get_nbobjs_by_depth(topology, depth) - 1);
if (obj) {
/* Get a copy of its cpuset that we may modify. */
cpuset = hwloc_bitmap_dup(obj->cpuset);
/* Get only one logical processor (in case the core is
SMT/hyper-threaded). */
hwloc_bitmap_singlify(cpuset);
/* And try to bind ourself there. */
if (hwloc_set_cpubind(topology, cpuset, 0)) {
char *str;
int error = errno;
hwloc_bitmap_asprintf(&str, obj->cpuset);
printf("Couldn't bind to cpuset %s: %s\n", str, strerror(error));
free(str);
}
/* Free our cpuset copy */
hwloc_bitmap_free(cpuset);
}
/*****************************************************************
* Sixth example:
* Allocate some memory on the last NUMA node, bind some existing
* memory to the last NUMA node.
*****************************************************************/
/* Get last node. There's always at least one. */
n = hwloc_get_nbobjs_by_type(topology, HWLOC_OBJ_NUMANODE);
obj = hwloc_get_obj_by_type(topology, HWLOC_OBJ_NUMANODE, n - 1);
size = 1024*1024;
m = hwloc_alloc_membind_nodeset(topology, size, obj->nodeset,
HWLOC_MEMBIND_BIND, 0);
hwloc_free(topology, m, size);
m = malloc(size);
hwloc_set_area_membind_nodeset(topology, m, size, obj->nodeset,
HWLOC_MEMBIND_BIND, 0);
free(m);
/* Destroy topology object. */
hwloc_topology_destroy(topology);
return 0;
}
