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)

Detailed Description

       Memory attribues are identified by an ID (hwloc_memattr_id_t) and a name. hwloc_memattr_get_name() and
       hwloc_memattr_get_by_name() convert between them (or return error if the attribute does not exist).

       The set of valid hwloc_memattr_id_t is a contigous set starting at 0. It first contains predefined
       attributes, as listed in hwloc_memattr_id_e (from 0 to HWLOC_MEMATTR_ID_MAX-1). Then custom attributes
       may be dynamically registered with hwloc_memattr_register(). They will get the following IDs
       (HWLOC_MEMATTR_ID_MAX for the first one, etc.).

       To iterate over all valid attributes (either predefined or dynamically registered custom ones), one may
       iterate over IDs starting from 0 until hwloc_memattr_get_name() or hwloc_memattr_get_flags() returns an
       error.

       The values for an existing attribute or for custom dynamically registered ones may be set or modified
       with hwloc_memattr_set_value().

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.

       The output pointer flags cannot be NULL.

       Returns
           0 on success.

           -1 with errno set to EINVAL if the attribute does not exist.

   int hwloc_memattr_get_name (hwloc_topology_t topology, hwloc_memattr_id_t attribute, const char ** name)
       Return the name of a memory attribute. The output pointer name cannot be NULL.

       Returns
           0 on success.

           -1 with errno set to EINVAL if the attribute does not exist.

   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  new  custom  memory  attribute.  Flags  are  a OR'ed set of
       hwloc_memattr_flag_e.    It    must     contain     one     of     HWLOC_MEMATTR_FLAG_HIGHER_FIRST     or
       HWLOC_MEMATTR_FLAG_LOWER_FIRST but not both.

       The  new  attribute id is immediately after the last existing attribute ID (which is either the ID of the
       last registered attribute if any, or the ID of the last predefined attribute in hwloc_memattr_id_e).

       Returns
           0 on success.

           -1 with errno set to EINVAL if an invalid set of flags is given.

           -1 with errno set to EBUSY if another attribute already uses this name.

   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.

       target_node cannot be NULL.

       attribute cannot be ::HWLOC_MEMATTR_FLAG_ID_CAPACITY or ::HWLOC_MEMATTR_FLAG_ID_LOCALITY.

       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.

       Returns
           0 on success or -1 on error.

Author

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Hardware Locality (hwloc)                        Version 2.12.0                    hwlocality_memattrs_manage(3)