hwlocality_object_types(3) Library Functions Manual
NAME
hwlocality_object_types - Object Types
SYNOPSIS
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
#define HWLOC_TYPE_UNORDERED
Value returned by hwloc_compare_types() when types can not be compared.
Typedef Documentation
typedef enum hwloc_obj_bridge_type_e hwloc_obj_bridge_type_t
Type of one side (upstream or downstream) of an I/O bridge.
typedef enum hwloc_obj_cache_type_e hwloc_obj_cache_type_t
Cache type.
typedef enum hwloc_obj_osdev_type_e hwloc_obj_osdev_type_t
Type of a OS device.
Enumeration Type Documentation
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.
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).
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.
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, hwloc will filter them out if all of them are
identical to packages. This is functionally equivalent to
HWLOC_TYPE_FILTER_KEEP_STRUCTURE being enforced for Dies versus
Packages.
Function Documentation
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.
Author
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the source code.
Hardware Locality (hwloc) Version 2.12.0 hwlocality_object_types(3)
hwloc 2.12.0 - Generated Fri May 9 07:19:24 CDT 2025