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Portable Hardware Locality (hwloc) Documentation: v1.9

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Object levels, depths and types

Enumerations

enum  hwloc_get_type_depth_e {
  HWLOC_TYPE_DEPTH_UNKNOWN, HWLOC_TYPE_DEPTH_MULTIPLE, HWLOC_TYPE_DEPTH_BRIDGE, HWLOC_TYPE_DEPTH_PCI_DEVICE,
  HWLOC_TYPE_DEPTH_OS_DEVICE
}
 

Functions

unsigned hwloc_topology_get_depth (hwloc_topology_t restrict topology)
 
int hwloc_get_type_depth (hwloc_topology_t topology, hwloc_obj_type_t type)
 
static int hwloc_get_type_or_below_depth (hwloc_topology_t topology, hwloc_obj_type_t type)
 
static int hwloc_get_type_or_above_depth (hwloc_topology_t topology, hwloc_obj_type_t type)
 
hwloc_obj_type_t hwloc_get_depth_type (hwloc_topology_t topology, unsigned depth)
 
unsigned hwloc_get_nbobjs_by_depth (hwloc_topology_t topology, unsigned depth)
 
static int hwloc_get_nbobjs_by_type (hwloc_topology_t topology, hwloc_obj_type_t type)
 
static hwloc_obj_t hwloc_get_root_obj (hwloc_topology_t topology)
 
hwloc_obj_t hwloc_get_obj_by_depth (hwloc_topology_t topology, unsigned depth, unsigned idx)
 
static hwloc_obj_t hwloc_get_obj_by_type (hwloc_topology_t topology, hwloc_obj_type_t type, unsigned idx)
 
static hwloc_obj_t hwloc_get_next_obj_by_depth (hwloc_topology_t topology, unsigned depth, hwloc_obj_t prev)
 
static hwloc_obj_t hwloc_get_next_obj_by_type (hwloc_topology_t topology, hwloc_obj_type_t type, hwloc_obj_t prev)
 

Detailed Description

Be sure to see the figure in Terms and Definitions that shows a complete topology tree, including depths, child/sibling/cousin relationships, and an example of an asymmetric topology where one socket has fewer caches than its peers.

Enumeration Type Documentation

Enumerator
HWLOC_TYPE_DEPTH_UNKNOWN 

No object of given type exists in the topology.

HWLOC_TYPE_DEPTH_MULTIPLE 

Objects of given type exist at different depth in the topology.

HWLOC_TYPE_DEPTH_BRIDGE 

Virtual depth for bridge object level.

HWLOC_TYPE_DEPTH_PCI_DEVICE 

Virtual depth for PCI device object level.

HWLOC_TYPE_DEPTH_OS_DEVICE 

Virtual depth for software device object level.

Function Documentation

hwloc_obj_type_t hwloc_get_depth_type ( hwloc_topology_t  topology,
unsigned  depth 
)

Returns the type of objects at depth depth.

Returns
-1 if depth depth does not exist.
unsigned hwloc_get_nbobjs_by_depth ( hwloc_topology_t  topology,
unsigned  depth 
)

Returns the width of level at depth depth.

static int hwloc_get_nbobjs_by_type ( hwloc_topology_t  topology,
hwloc_obj_type_t  type 
)
inlinestatic

Returns the width of level type type.

If no object for that type exists, 0 is returned. If there are several levels with objects of that type, -1 is returned.

static hwloc_obj_t hwloc_get_next_obj_by_depth ( hwloc_topology_t  topology,
unsigned  depth,
hwloc_obj_t  prev 
)
inlinestatic

Returns the next object at depth depth.

If prev is NULL, return the first object at depth depth.

static hwloc_obj_t hwloc_get_next_obj_by_type ( hwloc_topology_t  topology,
hwloc_obj_type_t  type,
hwloc_obj_t  prev 
)
inlinestatic

Returns the next object of type type.

If prev is NULL, return the first object at type type. If there are multiple or no depth for given type, return NULL and let the caller fallback to hwloc_get_next_obj_by_depth().

hwloc_obj_t hwloc_get_obj_by_depth ( hwloc_topology_t  topology,
unsigned  depth,
unsigned  idx 
)

Returns the topology object at logical index idx from depth depth.

static hwloc_obj_t hwloc_get_obj_by_type ( hwloc_topology_t  topology,
hwloc_obj_type_t  type,
unsigned  idx 
)
inlinestatic

Returns the topology object at logical index idx with type type.

If no object for that type exists, NULL is returned. If there are several levels with objects of that type, NULL is returned and ther caller may fallback to hwloc_get_obj_by_depth().

static hwloc_obj_t hwloc_get_root_obj ( hwloc_topology_t  topology)
inlinestatic

Returns the top-object of the topology-tree.

Its type is typically HWLOC_OBJ_MACHINE but it could be different for complex topologies.

int hwloc_get_type_depth ( hwloc_topology_t  topology,
hwloc_obj_type_t  type 
)

Returns the depth of objects of type type.

If no object of this type is present on the underlying architecture, or if the OS doesn't provide this kind of information, the function returns HWLOC_TYPE_DEPTH_UNKNOWN.

If type is absent but a similar type is acceptable, see also hwloc_get_type_or_below_depth() and hwloc_get_type_or_above_depth().

If some objects of the given type exist in different levels, for instance L1 and L2 caches, or L1i and L1d caches, the function returns HWLOC_TYPE_DEPTH_MULTIPLE. See hwloc_get_cache_type_depth() in hwloc/helper.h to better handle this case.

If an I/O object type is given, the function returns a virtual value because I/O objects are stored in special levels that are not CPU-related. This virtual depth may be passed to other hwloc functions such as hwloc_get_obj_by_depth() but it should not be considered as an actual depth by the application. In particular, it should not be compared with any other object depth or with the entire topology depth.

static int hwloc_get_type_or_above_depth ( hwloc_topology_t  topology,
hwloc_obj_type_t  type 
)
inlinestatic

Returns the depth of objects of type type or above.

If no object of this type is present on the underlying architecture, the function returns the depth of the first "present" object typically containing type.

If some objects of the given type exist in different levels, for instance L1 and L2 caches, the function returns HWLOC_TYPE_DEPTH_MULTIPLE.

static int hwloc_get_type_or_below_depth ( hwloc_topology_t  topology,
hwloc_obj_type_t  type 
)
inlinestatic

Returns the depth of objects of type type or below.

If no object of this type is present on the underlying architecture, the function returns the depth of the first "present" object typically found inside type.

If some objects of the given type exist in different levels, for instance L1 and L2 caches, the function returns HWLOC_TYPE_DEPTH_MULTIPLE.

unsigned hwloc_topology_get_depth ( hwloc_topology_t restrict  topology)

Get the depth of the hierarchical tree of objects.

This is the depth of HWLOC_OBJ_PU objects plus one.