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hwlocality_memattrs_manage(3)                          Hardware Locality (hwloc)




NAME

       hwlocality_memattrs_manage - Managing memory attributes


SYNOPSIS

   Enumerations
       enum hwloc_memattr_flag_e { HWLOC_MEMATTR_FLAG_HIGHER_FIRST = (1UL<<0),
           HWLOC_MEMATTR_FLAG_LOWER_FIRST = (1UL<<1),
           HWLOC_MEMATTR_FLAG_NEED_INITIATOR = (1UL<<2) }

   Functions
       int hwloc_memattr_get_name (hwloc_topology_t topology, hwloc_memattr_id_t
           attribute, const char **name)
       int hwloc_memattr_get_flags (hwloc_topology_t topology,
           hwloc_memattr_id_t attribute, unsigned long *flags)
       int hwloc_memattr_register (hwloc_topology_t topology, const char *name,
           unsigned long flags, hwloc_memattr_id_t *id)
       int hwloc_memattr_set_value (hwloc_topology_t topology,
           hwloc_memattr_id_t attribute, hwloc_obj_t target_node, struct
           hwloc_location *initiator, unsigned long flags, hwloc_uint64_t value)
       int hwloc_memattr_get_targets (hwloc_topology_t topology,
           hwloc_memattr_id_t attribute, struct hwloc_location *initiator,
           unsigned long flags, unsigned *nr, hwloc_obj_t *targets,
           hwloc_uint64_t *values)
       int hwloc_memattr_get_initiators (hwloc_topology_t topology,
           hwloc_memattr_id_t attribute, hwloc_obj_t target_node, unsigned long
           flags, unsigned *nr, struct hwloc_location *initiators,
           hwloc_uint64_t *values)


Detailed Description


Enumeration Type Documentation

   enum hwloc_memattr_flag_e
       Memory attribute flags. Given to hwloc_memattr_register() and returned by
       hwloc_memattr_get_flags().

       Enumerator

       HWLOC_MEMATTR_FLAG_HIGHER_FIRST
              The best nodes for this memory attribute are those with the higher
              values. For instance Bandwidth.

       HWLOC_MEMATTR_FLAG_LOWER_FIRST
              The best nodes for this memory attribute are those with the lower
              values. For instance Latency.

       HWLOC_MEMATTR_FLAG_NEED_INITIATOR
              The value returned for this memory attribute depends on the given
              initiator. For instance Bandwidth and Latency, but not Capacity.


Function Documentation

   int hwloc_memattr_get_flags (hwloc_topology_t topology, hwloc_memattr_id_t
       attribute, unsigned long * flags)
       Return the flags of the given attribute. Flags are a OR'ed set of
       hwloc_memattr_flag_e.

   int hwloc_memattr_get_initiators (hwloc_topology_t topology,
       hwloc_memattr_id_t attribute, hwloc_obj_t target_node, unsigned long
       flags, unsigned * nr, struct hwloc_location * initiators, hwloc_uint64_t
       * values)
       Return the initiators that have values for a given attribute for a
       specific target NUMA node. Return initiators for the given attribute and
       target node in the initiators array. If values is not NULL, the
       corresponding attribute values are stored in the array it points to.

       On input, nr points to the number of initiators that may be stored in the
       array initiators (and values). On output, nr points to the number of
       initiators (and values) that were actually found, even if some of them
       couldn't be stored in the array. Initiators 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.

       The returned initiators should not be modified or freed, they belong to
       the topology.

       flags must be 0 for now.

       If the attribute does not relate to a specific initiator (it does not
       have the flag HWLOC_MEMATTR_FLAG_NEED_INITIATOR), no initiator is
       returned.

       Note
           This function is meant for tools and debugging (listing internal
           information) rather than for application queries. Applications should
           rather select useful NUMA nodes with hwloc_get_local_numanode_objs()
           and then look at their attribute values for some relevant initiators.

   int hwloc_memattr_get_name (hwloc_topology_t topology, hwloc_memattr_id_t
       attribute, const char ** name)
       Return the name of a memory attribute.

   int hwloc_memattr_get_targets (hwloc_topology_t topology, hwloc_memattr_id_t
       attribute, struct hwloc_location * initiator, unsigned long flags,
       unsigned * nr, hwloc_obj_t * targets, hwloc_uint64_t * values)
       Return the target NUMA nodes that have some values for a given attribute.
       Return targets for the given attribute in the targets array (for the
       given initiator if any). If values is not NULL, the corresponding
       attribute values are stored in the array it points to.

       On input, nr points to the number of targets that may be stored in the
       array targets (and values). On output, nr points to the number of targets
       (and values) that were actually found, even if some of them couldn't be
       stored in the array. Targets 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.

       The returned targets should not be modified or freed, they belong to the
       topology.

       Argument initiator is ignored if the attribute does not relate to a
       specific initiator (it does not have the flag
       HWLOC_MEMATTR_FLAG_NEED_INITIATOR). Otherwise initiator may be non NULL
       to report only targets that have a value for that initiator.

       flags must be 0 for now.

       Note
           This function is meant for tools and debugging (listing internal
           information) rather than for application queries. Applications should
           rather select useful NUMA nodes with hwloc_get_local_numanode_objs()
           and then look at their attribute values.

           The initiator initiator should be of type HWLOC_LOCATION_TYPE_CPUSET
           when referring to accesses performed by CPU cores.
           HWLOC_LOCATION_TYPE_OBJECT is currently unused internally by hwloc,
           but users may for instance use it to provide custom information about
           host memory accesses performed by GPUs.

   int hwloc_memattr_register (hwloc_topology_t topology, const char * name,
       unsigned long flags, hwloc_memattr_id_t * id)
       Register a new memory attribute. Add a specific memory attribute that is
       not defined in hwloc_memattr_id_e. Flags are a OR'ed set of
       hwloc_memattr_flag_e. It must contain at least one of
       HWLOC_MEMATTR_FLAG_HIGHER_FIRST or HWLOC_MEMATTR_FLAG_LOWER_FIRST.

   int hwloc_memattr_set_value (hwloc_topology_t topology, hwloc_memattr_id_t
       attribute, hwloc_obj_t target_node, struct hwloc_location * initiator,
       unsigned long flags, hwloc_uint64_t value)
       Set an attribute value for a specific target NUMA node. If the attribute
       does not relate to a specific initiator (it does not have the flag
       HWLOC_MEMATTR_FLAG_NEED_INITIATOR), location initiator is ignored and may
       be NULL.

       The initiator will be copied into the topology, the caller should free
       anything allocated to store the initiator, for instance the cpuset.

       flags must be 0 for now.

       Note
           The initiator initiator should be of type HWLOC_LOCATION_TYPE_CPUSET
           when referring to accesses performed by CPU cores.
           HWLOC_LOCATION_TYPE_OBJECT is currently unused internally by hwloc,
           but users may for instance use it to provide custom information about
           host memory accesses performed by GPUs.


Author

       Generated automatically by Doxygen for Hardware Locality (hwloc) from the
       source code.



Version 2.7.1                    Sun Mar 20 2022   hwlocality_memattrs_manage(3)

hwloc 2.7.1 - Generated Tue Jun 14 11:33:22 CDT 2022
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