hwloc_distances_s(3) Hardware Locality (hwloc) hwloc_distances_s(3)
NAME
hwloc_distances_s
SYNOPSIS
#include <distances.h>
Data Fields
unsigned nbobjs
hwloc_obj_t * objs
unsigned long kind
hwloc_uint64_t * values
Detailed Description
Matrix of distances between a set of objects.
This matrix often contains latencies between NUMA nodes (as reported in
the System Locality Distance Information Table (SLIT) in the ACPI
specification), which may or may not be physically accurate. It
corresponds to the latency for accessing the memory of one node from a
core in another node. The corresponding kind is
HWLOC_DISTANCES_KIND_FROM_OS | HWLOC_DISTANCES_KIND_FROM_USER. The name
of this distances structure is 'NUMALatency'. Others distance
structures include and 'XGMIBandwidth', 'XGMIHops' and
'NVLinkBandwidth'.
The matrix may also contain bandwidths between random sets of objects,
possibly provided by the user, as specified in the kind attribute.
Pointers objs and values should not be replaced, reallocated, freed,
etc. However callers are allowed to modify kind as well as the contents
of objs and values arrays. For instance, if there is a single NUMA node
per Package, hwloc_get_obj_with_same_locality() may be used to convert
between them and replace NUMA nodes in the objs array with the
corresponding Packages. See also hwloc_distances_transform() for
applying some transformations to the structure.
Field Documentation
unsigned long hwloc_distances_s::kind
OR'ed set of hwloc_distances_kind_e.
unsigned hwloc_distances_s::nbobjs
Number of objects described by the distance matrix.
hwloc_obj_t* hwloc_distances_s::objs
Array of objects described by the distance matrix. These objects are
not in any particular order, see hwloc_distances_obj_index() and
hwloc_distances_obj_pair_values() for easy ways to find objects in this
array and their corresponding values.
hwloc_uint64_t* hwloc_distances_s::values
Matrix of distances between objects, stored as a one-dimension array.
Distance from i-th to j-th object is stored in slot i*nbobjs+j. The
meaning of the value depends on the kind attribute.
Author
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