NAME

       hwlocality_distances_get

SYNOPSIS

   Data Structures
       struct hwloc_distances_s

   Enumerations
       enum hwloc_distances_kind_e { HWLOC_DISTANCES_KIND_FROM_OS,
           HWLOC_DISTANCES_KIND_FROM_USER, HWLOC_DISTANCES_KIND_MEANS_LATENCY,
           HWLOC_DISTANCES_KIND_MEANS_BANDWIDTH, HWLOC_DISTANCES_KIND_HETEROGENEOUS_TYPES }

   Functions
       int hwloc_distances_get (hwloc_topology_t topology, unsigned *nr, struct hwloc_distances_s
           **distances, unsigned long kind, unsigned long flags)
       int hwloc_distances_get_by_depth (hwloc_topology_t topology, int depth, unsigned *nr,
           struct hwloc_distances_s **distances, unsigned long kind, unsigned long flags)
       int hwloc_distances_get_by_type (hwloc_topology_t topology, hwloc_obj_type_t type,
           unsigned *nr, struct hwloc_distances_s **distances, unsigned long kind, unsigned long
           flags)
       int hwloc_distances_get_by_name (hwloc_topology_t topology, const char *name, unsigned
           *nr, struct hwloc_distances_s **distances, unsigned long flags)
       const char * hwloc_distances_get_name (hwloc_topology_t topology, struct hwloc_distances_s
           *distances)
       void hwloc_distances_release (hwloc_topology_t topology, struct hwloc_distances_s
           *distances)

Detailed Description

Enumeration Type Documentation

   enum hwloc_distances_kind_e
       Kinds of distance matrices. The kind attribute of struct hwloc_distances_s is a OR'ed set
       of kinds.

       A kind of format HWLOC_DISTANCES_KIND_FROM_* specifies where the distance information
       comes from, if known.

       A kind of format HWLOC_DISTANCES_KIND_MEANS_* specifies whether values are latencies or
       bandwidths, if applicable.

       Enumerator

       HWLOC_DISTANCES_KIND_FROM_OS
              These distances were obtained from the operating system or hardware.

       HWLOC_DISTANCES_KIND_FROM_USER
              These distances were provided by the user.

       HWLOC_DISTANCES_KIND_MEANS_LATENCY
              Distance values are similar to latencies between objects. Values are smaller for
              closer objects, hence minimal on the diagonal of the matrix (distance between an
              object and itself). It could also be the number of network hops between objects,
              etc.

       HWLOC_DISTANCES_KIND_MEANS_BANDWIDTH
              Distance values are similar to bandwidths between objects. Values are higher for
              closer objects, hence maximal on the diagonal of the matrix (distance between an
              object and itself). Such values are currently ignored for distance-based grouping.

       HWLOC_DISTANCES_KIND_HETEROGENEOUS_TYPES
              This distances structure covers objects of different types.

Function Documentation

   int hwloc_distances_get (hwloc_topology_t topology, unsigned * nr, struct hwloc_distances_s **
       distances, unsigned long kind, unsigned long flags)
       Retrieve distance matrices. Retrieve distance matrices from the topology into the
       distances array.

       flags is currently unused, should be 0.

       kind serves as a filter. If 0, all distance matrices are returned. If it contains some
       HWLOC_DISTANCES_KIND_FROM_*, only distance matrices whose kind matches one of these are
       returned. If it contains some HWLOC_DISTANCES_KIND_MEANS_*, only distance matrices whose
       kind matches one of these are returned.

       On input, nr points to the number of distance matrices that may be stored in distances. On
       output, nr points to the number of distance matrices that were actually found, even if
       some of them couldn't be stored in distances. Distance matrices that couldn't be stored
       are ignored, but the function still returns success (0). The caller may find out by
       comparing the value pointed by nr before and after the function call.

       Each distance matrix returned in the distances array should be released by the caller
       using hwloc_distances_release().

   int hwloc_distances_get_by_depth (hwloc_topology_t topology, int depth, unsigned * nr, struct
       hwloc_distances_s ** distances, unsigned long kind, unsigned long flags)
       Retrieve distance matrices for object at a specific depth in the topology. Identical to
       hwloc_distances_get() with the additional depth filter.

   int hwloc_distances_get_by_name (hwloc_topology_t topology, const char * name, unsigned * nr,
       struct hwloc_distances_s ** distances, unsigned long flags)
       Retrieve a distance matrix with the given name. Usually only one distances structure may
       match a given name.

   int hwloc_distances_get_by_type (hwloc_topology_t topology, hwloc_obj_type_t type, unsigned *
       nr, struct hwloc_distances_s ** distances, unsigned long kind, unsigned long flags)
       Retrieve distance matrices for object of a specific type. Identical to
       hwloc_distances_get() with the additional type filter.

   const char* hwloc_distances_get_name (hwloc_topology_t topology, struct hwloc_distances_s *
       distances)
       Get a description of what a distances structure contains. For instance 'NUMALatency' for
       hardware-provided NUMA distances (ACPI SLIT), or NULL if unknown.

   void hwloc_distances_release (hwloc_topology_t topology, struct hwloc_distances_s * distances)
       Release a distance matrix structure previously returned by hwloc_distances_get().

       Note:
           This function is not required if the structure is removed with
           hwloc_distances_release_remove().

Author

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