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NAME

       Configure Topology Detection -

   Data Structures
       struct hwloc_topology_discovery_support
           Flags describing actual discovery support for this topology.
       struct hwloc_topology_cpubind_support
           Flags describing actual binding support for this topology.
       struct hwloc_topology_support
           Set of flags describing actual support for this topology.

   Enumerations
       enum hwloc_topology_flags_e { HWLOC_TOPOLOGY_FLAG_WHOLE_SYSTEM,
           HWLOC_TOPOLOGY_FLAG_IS_THISSYSTEM }
           Flags to be set onto a topology context before load.

   Functions
       HWLOC_DECLSPEC int hwloc_topology_ignore_type (hwloc_topology_t
           topology, hwloc_obj_type_t type)
           Ignore an object type.
       HWLOC_DECLSPEC int hwloc_topology_ignore_type_keep_structure
           (hwloc_topology_t topology, hwloc_obj_type_t type)
           Ignore an object type if it does not bring any structure.
       HWLOC_DECLSPEC int hwloc_topology_ignore_all_keep_structure
           (hwloc_topology_t topology)
           Ignore all objects that do not bring any structure.
       HWLOC_DECLSPEC int hwloc_topology_set_flags (hwloc_topology_t topology,
           unsigned long flags)
           Set ORed flags to non-yet-loaded topology.
       HWLOC_DECLSPEC int hwloc_topology_set_fsroot (hwloc_topology_t
           __hwloc_restrict topology, const char *__hwloc_restrict
           fsroot_path)
           Change the file-system root path when building the topology from
           sysfs/procfs.
       HWLOC_DECLSPEC int hwloc_topology_set_pid (hwloc_topology_t
           __hwloc_restrict topology, hwloc_pid_t pid)
           Change which pid the topology is viewed from.
       HWLOC_DECLSPEC int hwloc_topology_set_synthetic (hwloc_topology_t
           __hwloc_restrict topology, const char *__hwloc_restrict
           description)
           Enable synthetic topology.
       HWLOC_DECLSPEC int hwloc_topology_set_xml (hwloc_topology_t
           __hwloc_restrict topology, const char *__hwloc_restrict xmlpath)
           Enable XML-file based topology.
       HWLOC_DECLSPEC struct hwloc_topology_support *
           hwloc_topology_get_support (hwloc_topology_t __hwloc_restrict
           topology)
           Retrieve the topology support.

Detailed Description

       These functions can optionally be called between hwloc_topology_init()
       and hwloc_topology_load() to configure how the detection should be
       performed, e.g. to ignore some objects types, define a synthetic
       topology, etc.

       If none of them is called, the default is to detect all the objects of
       the machine that the caller is allowed to access.

       This default behavior may also be modified through environment
       variables if the application did not modify it already. Setting
       HWLOC_XMLFILE in the environment enforces the discovery from a XML file
       as if hwloc_topology_set_xml() had been called. HWLOC_FSROOT switches
       to reading the topology from the specified Linux filesystem root as if
       hwloc_topology_set_fsroot() had been called. Finally, HWLOC_THISSYSTEM
       enforces the return value of hwloc_topology_is_thissystem().

Enumeration Type Documentation

   enum hwloc_topology_flags_e
       Flags to be set onto a topology context before load. Flags should be
       given to hwloc_topology_set_flags().

       Enumerator:

       HWLOC_TOPOLOGY_FLAG_WHOLE_SYSTEM
              Detect the whole system, ignore reservations and offline
              settings. Gather all resources, even if some were disabled by
              the administrator. For instance, ignore Linux Cpusets and gather
              all processors and memory nodes, and ignore the fact that some
              resources may be offline.

       HWLOC_TOPOLOGY_FLAG_IS_THISSYSTEM
              Assume that the selected backend provides the topology for the
              system on which we are running. This forces
              hwloc_topology_is_thissystem to return 1, i.e. makes hwloc
              assume that the selected backend provides the topology for the
              system on which we are running, even if it is not the OS-
              specific backend but the XML backend for instance. This means
              making the binding functions actually call the OS-specific
              system calls and really do binding, while the XML backend would
              otherwise provide empty hooks just returning success.

       Setting the environment variable HWLOC_THISSYSTEM may also result in
       the same behavior.

       This can be used for efficiency reasons to first detect the topology
       once, save it to an XML file, and quickly reload it later through the
       XML backend, but still having binding functions actually do bind.

Function Documentation

   HWLOC_DECLSPEC struct hwloc_topology_support* hwloc_topology_get_support
       (hwloc_topology_t __hwloc_restrict topology) [read]
       Retrieve the topology support.

   HWLOC_DECLSPEC int hwloc_topology_ignore_all_keep_structure
       (hwloc_topology_t topology)
       Ignore all objects that do not bring any structure. Ignore all objects
       that do not bring any structure: Each ignored object should have a
       single children or be the only child of its parent.

   HWLOC_DECLSPEC int hwloc_topology_ignore_type (hwloc_topology_t topology,
       hwloc_obj_type_t type)
       Ignore an object type. Ignore all objects from the given type. The
       bottom-level type HWLOC_OBJ_PU may not be ignored. The top-level object
       of the hierarchy will never be ignored, even if this function succeeds.

   HWLOC_DECLSPEC int hwloc_topology_ignore_type_keep_structure
       (hwloc_topology_t topology, hwloc_obj_type_t type)
       Ignore an object type if it does not bring any structure. Ignore all
       objects from the given type as long as they do not bring any structure:
       Each ignored object should have a single children or be the only child
       of its parent. The bottom-level type HWLOC_OBJ_PU may not be ignored.

   HWLOC_DECLSPEC int hwloc_topology_set_flags (hwloc_topology_t topology,
       unsigned long flags)
       Set OR’ed flags to non-yet-loaded topology. Set a OR’ed set of
       hwloc_topology_flags_e onto a topology that was not yet loaded.

   HWLOC_DECLSPEC int hwloc_topology_set_fsroot (hwloc_topology_t
       __hwloc_restrict topology, const char *__hwloc_restrict fsroot_path)
       Change the file-system root path when building the topology from
       sysfs/procfs. On Linux system, use sysfs and procfs files as if they
       were mounted on the given fsroot_path instead of the main file-system
       root. Setting the environment variable HWLOC_FSROOT may also result in
       this behavior. Not using the main file-system root causes
       hwloc_topology_is_thissystem() to return 0.

       Note:
           For conveniency, this backend provides empty binding hooks which
           just return success. To have hwloc still actually call OS-specific
           hooks, the HWLOC_TOPOLOGY_FLAG_IS_THISSYSTEM has to be set to
           assert that the loaded file is really the underlying system.

   HWLOC_DECLSPEC int hwloc_topology_set_pid (hwloc_topology_t
       __hwloc_restrict topology, hwloc_pid_t pid)
       Change which pid the topology is viewed from. On some systems,
       processes may have different views of the machine, for instance the set
       of allowed CPUs. By default, hwloc exposes the view from the current
       process. Calling hwloc_topology_set_pid() permits to make it expose the
       topology of the machine from the point of view of another process.

       Note:
           hwloc_pid_t is pid_t on unix platforms, and HANDLE on native
           Windows platforms

           The ENOSYS error is returned on platforms that does not support
           this feature.

   HWLOC_DECLSPEC int hwloc_topology_set_synthetic (hwloc_topology_t
       __hwloc_restrict topology, const char *__hwloc_restrict description)
       Enable synthetic topology. Gather topology information from the given
       description which should be a comma separated string of numbers
       describing the arity of each level. Each number may be prefixed with a
       type and a colon to enforce the type of a level. If only some level
       types are enforced, hwloc will try to choose the other types according
       to usual topologies, but it may fail and you may have to specify more
       level types manually.

       Note:
           For conveniency, this backend provides empty binding hooks which
           just return success.

   HWLOC_DECLSPEC int hwloc_topology_set_xml (hwloc_topology_t
       __hwloc_restrict topology, const char *__hwloc_restrict xmlpath)
       Enable XML-file based topology. Gather topology information the XML
       file given at xmlpath. Setting the environment variable HWLOC_XMLFILE
       may also result in this behavior. This file may have been generated
       earlier with lstopo file.xml.

       Note:
           For conveniency, this backend provides empty binding hooks which
           just return success. To have hwloc still actually call OS-specific
           hooks, the HWLOC_TOPOLOGY_FLAG_IS_THISSYSTEM has to be set to
           assert that the loaded file is really the underlying system.

Author

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