Object Types

## Macros

#define | HWLOC_TYPE_UNORDERED

## Typedefs

typedef enum hwloc_obj_cache_type_e | hwloc_obj_cache_type_t
typedef enum hwloc_obj_bridge_type_e | hwloc_obj_bridge_type_t
typedef enum hwloc_obj_osdev_type_e | hwloc_obj_osdev_type_t

## Enumerations

enum

hwloc_obj_type_t {
HWLOC_OBJ_MACHINE , HWLOC_OBJ_PACKAGE , HWLOC_OBJ_CORE , HWLOC_OBJ_PU ,
HWLOC_OBJ_L1CACHE , HWLOC_OBJ_L2CACHE , HWLOC_OBJ_L3CACHE , HWLOC_OBJ_L4CACHE ,
HWLOC_OBJ_L5CACHE , HWLOC_OBJ_L1ICACHE , HWLOC_OBJ_L2ICACHE , HWLOC_OBJ_L3ICACHE ,
HWLOC_OBJ_GROUP , HWLOC_OBJ_NUMANODE , HWLOC_OBJ_BRIDGE , HWLOC_OBJ_PCI_DEVICE ,
HWLOC_OBJ_OS_DEVICE , HWLOC_OBJ_MISC , HWLOC_OBJ_MEMCACHE , HWLOC_OBJ_DIE ,
HWLOC_OBJ_TYPE_MAX
}

enum | hwloc_obj_cache_type_e { HWLOC_OBJ_CACHE_UNIFIED , HWLOC_OBJ_CACHE_DATA , HWLOC_OBJ_CACHE_INSTRUCTION }
enum | hwloc_obj_bridge_type_e { HWLOC_OBJ_BRIDGE_HOST , HWLOC_OBJ_BRIDGE_PCI }
enum | hwloc_obj_osdev_type_e { HWLOC_OBJ_OSDEV_BLOCK , HWLOC_OBJ_OSDEV_GPU , HWLOC_OBJ_OSDEV_NETWORK , HWLOC_OBJ_OSDEV_OPENFABRICS , HWLOC_OBJ_OSDEV_DMA , HWLOC_OBJ_OSDEV_COPROC }

## Functions

int | hwloc_compare_types (hwloc_obj_type_t type1, hwloc_obj_type_t type2)

## Detailed Description

## Macro Definition Documentation

## HWLOC_TYPE_UNORDERED

#define HWLOC_TYPE_UNORDERED

Value returned by hwloc_compare_types() when types can not be compared.

## Typedef Documentation

## hwloc_obj_bridge_type_t

typedef enum hwloc_obj_bridge_type_e hwloc_obj_bridge_type_t

Type of one side (upstream or downstream) of an I/O bridge.

## hwloc_obj_cache_type_t

typedef enum hwloc_obj_cache_type_e hwloc_obj_cache_type_t

Cache type.

## hwloc_obj_osdev_type_t

typedef enum hwloc_obj_osdev_type_e hwloc_obj_osdev_type_t

Type of a OS device.

## Enumeration Type Documentation

## hwloc_obj_bridge_type_e

enum hwloc_obj_bridge_type_e

Type of one side (upstream or downstream) of an I/O bridge.

Enumerator
HWLOC_OBJ_BRIDGE_HOST | Host-side of a bridge, only possible upstream.
HWLOC_OBJ_BRIDGE_PCI | PCI-side of a bridge.

## hwloc_obj_cache_type_e

enum hwloc_obj_cache_type_e

Cache type.

Enumerator
HWLOC_OBJ_CACHE_UNIFIED | Unified cache.
HWLOC_OBJ_CACHE_DATA | Data cache.
HWLOC_OBJ_CACHE_INSTRUCTION | Instruction cache (filtered out by default).

## hwloc_obj_osdev_type_e

enum hwloc_obj_osdev_type_e

Type of a OS device.

Enumerator
HWLOC_OBJ_OSDEV_BLOCK | Operating system block device, or non-volatile memory device. For instance "sda" or "dax2.0" on Linux.
HWLOC_OBJ_OSDEV_GPU | Operating system GPU device. For instance ":0.0" for a GL display, "card0" for a Linux DRM device.
HWLOC_OBJ_OSDEV_NETWORK | Operating system network device. For instance the "eth0" interface on Linux.
HWLOC_OBJ_OSDEV_OPENFABRICS | Operating system openfabrics device. For instance the "mlx4_0" InfiniBand HCA, "hfi1_0" Omni-Path interface, or "bxi0" Atos/Bull BXI HCA on Linux.
HWLOC_OBJ_OSDEV_DMA | Operating system dma engine device. For instance the "dma0chan0" DMA channel on Linux.
HWLOC_OBJ_OSDEV_COPROC | Operating system co-processor device. For instance "opencl0d0" for a OpenCL device, "cuda0" for a CUDA device.

## hwloc_obj_type_t

enum hwloc_obj_type_t

Type of topology object.

Note
  Do not rely on the ordering or completeness of the values as new ones may be defined in the future! If you need to compare types, use hwloc_compare_types() instead.

Enumerator
HWLOC_OBJ_MACHINE | Machine. A set of processors and memory with cache coherency. This type is always used for the root object of a topology, and never used anywhere else. Hence its parent is always `NULL`.
HWLOC_OBJ_PACKAGE | Physical package. The physical package that usually gets inserted into a socket on the motherboard. A processor package usually contains multiple cores, and possibly some dies.
HWLOC_OBJ_CORE | Core. A computation unit (may be shared by several PUs, aka logical processors).
HWLOC_OBJ_PU | Processing Unit, or (Logical) Processor. An execution unit (may share a core with some other logical processors, e.g. in the case of an SMT core). This is the smallest object representing CPU resources, it cannot have any child except Misc objects. Objects of this kind are always reported and can thus be used as fallback when others are not.
HWLOC_OBJ_L1CACHE | Level 1 Data (or Unified) Cache.
HWLOC_OBJ_L2CACHE | Level 2 Data (or Unified) Cache.
HWLOC_OBJ_L3CACHE | Level 3 Data (or Unified) Cache.
HWLOC_OBJ_L4CACHE | Level 4 Data (or Unified) Cache.
HWLOC_OBJ_L5CACHE | Level 5 Data (or Unified) Cache.
HWLOC_OBJ_L1ICACHE | Level 1 instruction Cache (filtered out by default).
HWLOC_OBJ_L2ICACHE | Level 2 instruction Cache (filtered out by default).
HWLOC_OBJ_L3ICACHE | Level 3 instruction Cache (filtered out by default).

HWLOC_OBJ_GROUP

Group objects. Objects which do not fit in the above but are detected by hwloc and are useful to take into account for affinity. For instance, some operating systems expose their arbitrary processors aggregation this way. And hwloc may insert such objects to group NUMA nodes according to their distances. See also What are these Group objects in my topology?.

These objects are removed when they do not bring any structure (see HWLOC_TYPE_FILTER_KEEP_STRUCTURE).

HWLOC_OBJ_NUMANODE

NUMA node. An object that contains memory that is directly and byte-accessible to the host processors. It is usually close to some cores (the corresponding objects are descendants of the NUMA node object in the hwloc tree).

This is the smallest object representing Memory resources, it cannot have any child except Misc objects. However it may have Memory-side cache parents.

NUMA nodes may correspond to different kinds of memory (DRAM, HBM, CXL-DRAM, etc.). When hwloc is able to guess that kind, it is specified in the subtype field of the object. See also Normal attributes in the main documentation.

There is always at least one such object in the topology even if the machine is not NUMA.

Memory objects are not listed in the main children list, but rather in the dedicated Memory children list.

NUMA nodes have a special depth HWLOC_TYPE_DEPTH_NUMANODE instead of a normal depth just like other objects in the main tree.

HWLOC_OBJ_BRIDGE

Bridge (filtered out by default). Any bridge (or PCI switch) that connects the host or an I/O bus, to another I/O bus.

Bridges are not added to the topology unless their filtering is changed (see hwloc_topology_set_type_filter() and hwloc_topology_set_io_types_filter()).

I/O objects are not listed in the main children list, but rather in the dedicated io children list. I/O objects have NULL CPU and node sets.

HWLOC_OBJ_PCI_DEVICE | PCI device (filtered out by default). PCI devices are not added to the topology unless their filtering is changed (see hwloc_topology_set_type_filter() and hwloc_topology_set_io_types_filter()). I/O objects are not listed in the main children list, but rather in the dedicated io children list. I/O objects have NULL CPU and node sets.
HWLOC_OBJ_OS_DEVICE | Operating system device (filtered out by default). OS devices are not added to the topology unless their filtering is changed (see hwloc_topology_set_type_filter() and hwloc_topology_set_io_types_filter()). I/O objects are not listed in the main children list, but rather in the dedicated io children list. I/O objects have NULL CPU and node sets.

HWLOC_OBJ_MISC

Miscellaneous objects (filtered out by default). Objects without particular meaning, that can e.g. be added by the application for its own use, or by hwloc for miscellaneous objects such as MemoryModule (DIMMs).

They are not added to the topology unless their filtering is changed (see hwloc_topology_set_type_filter()).

These objects are not listed in the main children list, but rather in the dedicated misc children list. Misc objects may only have Misc objects as children, and those are in the dedicated misc children list as well. Misc objects have NULL CPU and node sets.

HWLOC_OBJ_MEMCACHE

Memory-side cache (filtered out by default). A cache in front of a specific NUMA node.

This object always has at least one NUMA node as a memory child.

Memory objects are not listed in the main children list, but rather in the dedicated Memory children list.

Memory-side cache have a special depth HWLOC_TYPE_DEPTH_MEMCACHE instead of a normal depth just like other objects in the main tree.

HWLOC_OBJ_DIE

Die within a physical package. A subpart of the physical package, that contains multiple cores.

Some operating systems (e.g. Linux) may expose a single die per package even if the hardware does not support dies at all. To avoid showing such non-existing dies, the corresponding hwloc backend may filter them out. This is functionally equivalent to HWLOC_TYPE_FILTER_KEEP_STRUCTURE being enforced.

## Function Documentation

## hwloc_compare_types()

int hwloc_compare_types | ( | hwloc_obj_type_t | type1,
|  | hwloc_obj_type_t | type2
| ) |  |

Compare the depth of two object types.

Types shouldn't be compared as they are, since newer ones may be added in the future.

Returns
  A negative integer if `type1` objects usually include `type2` objects.
  A positive integer if `type1` objects are usually included in `type2` objects.
  0 if `type1` and `type2` objects are the same.
  HWLOC_TYPE_UNORDERED if objects cannot be compared (because neither is usually contained in the other).

Note
  Object types containing CPUs can always be compared (usually, a machine contains packages, which contain caches, which contain cores, which contain PUs).
  HWLOC_OBJ_PU will always be the deepest, while HWLOC_OBJ_MACHINE is always the highest.
  This does not mean that the actual topology will respect that order: e.g. as of today cores may also contain caches, and packages may also contain nodes. This is thus just to be seen as a fallback comparison method.