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Portable Hardware Locality (hwloc) Documentation: v1.2.1

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hwloc_distances_s Struct Reference

Distances between objects. More...

#include <hwloc.h>

Data Fields

unsigned relative_depth
 Relative depth of the considered objects below the object containing this distance information.
unsigned nbobjs
 Number of objects considered in the matrix. It is the number of descendant objects at relative_depth below the containing object. It corresponds to the result of hwloc_get_nbobjs_inside_cpuset_by_depth.
float * latency
 Matrix of latencies between objects, stored as a one-dimension array. May be NULL if the distances considered here are not latencies. Values are normalized to get 1.0 as the minimal value in the matrix. Latency from i-th to j-th object is stored in slot i*nbobjs+j.
float latency_max
 The maximal value in the latency matrix.
float latency_base
 The multiplier that should be applied to latency matrix to retrieve the original OS-provided latencies. Usually 10 on Linux since ACPI SLIT uses 10 for local latency.

Detailed Description

Distances between objects.

One object may contain a distance structure describing distances between all its descendants at a given relative depth. If the containing object is the root object of the topology, then the distances are available for all objects in the machine.

The distance may be a memory latency, as defined by the ACPI SLIT specification. If so, the latency pointer will not be NULL and the pointed array will contain non-zero values.

In the future, some other types of distances may be considered. In these cases, latency will be NULL.


Field Documentation

Matrix of latencies between objects, stored as a one-dimension array. May be NULL if the distances considered here are not latencies. Values are normalized to get 1.0 as the minimal value in the matrix. Latency from i-th to j-th object is stored in slot i*nbobjs+j.

The multiplier that should be applied to latency matrix to retrieve the original OS-provided latencies. Usually 10 on Linux since ACPI SLIT uses 10 for local latency.

The maximal value in the latency matrix.

Number of objects considered in the matrix. It is the number of descendant objects at relative_depth below the containing object. It corresponds to the result of hwloc_get_nbobjs_inside_cpuset_by_depth.

Relative depth of the considered objects below the object containing this distance information.


The documentation for this struct was generated from the following file: