NAME    [Toc]    [Back]

       nloc  -  Queries  the  NUMA  Topology or Resource Affinity
       Domains (libnuma library)

SYNOPSIS    [Toc]    [Back]

       #include <numa.h>

       int nloc(
               numa_attr_t *numa_attr,
               radset_t radset );

PARAMETERS    [Toc]    [Back]

       Points to a structure  that  specifies  the  criteria  for
       selecting  a set of resource Affinity Domains (RADs). This
       structure contains the following  elements:  The  type  of
       resource  for which the set of "nearby" RADs is requested.
       The  resource  descriptor  for  which  the  RAD   set   is
       requested.  The distance criteria for selecting resources.
       RADs in the caller's partition that  have  a  distance  <=
       this  value  will  be  included  in the radset returned by
       nloc().  See  DESCRIPTION  for  more   information   about
       nattr_distance.   Flags  that  influence  the selection of
       RADs. See DESCRIPTION for details.  Specifies a buffer  to
       contain  the  set  of  RADs in the caller's partition that
       satisfy the criteria specified by numa_attr.

DESCRIPTION    [Toc]    [Back]

       The nloc() function will return in radset the set of  RADs
       that  have a distance <= the nattr_distance value from the
       specified resource.  The returned radset value may be used
       as  an  argument  to  explicit process or thread placement
       APIs or in the mattr_radset member of a memory  allocation
       policy structure for explicit memory placement.

       The  following  symbolic  values  for  nattr_distance  are
       defined: Represents the distance value for resources  that
       are  directly connected to the specified resource.  Represents
 the maximum distance value for the  system.   Generally,
  all RADs in the partition will be <= this distance.

       For NUMA topologies in which RADs are  variable  distances
       from  one  another,  RAD_DIST_LOCAL  can be incremented to
       specify   a   specific   distance.    In   other    words,
       RAD_DIST_LOCAL  + 1 represents the distance to the closest
       RADs, RAD_DIST_LOCAL + 2 represents the  distance  to  the
       next  closest  RADs,  and  so  forth.  For  example,  when
       nattr_distance  is  set  to  RAD_DIST_LOCAL  +  2,  nloc()
       returns  in radset the set of RADs that have a distance <=
       (RAD_DIST_LOCAL + 2) from the specified resource. For NUMA
       topologies   where  all  RADs  are  equidistant  from  one
       another, <= (RAD_DIST_LOCAL + n), where n  is  a  positive
       integer, is equivalent to <= RAD_DIST_REMOTE.

       The   following   symbolic  values  are  defined  for  the
       nattr_flags field: When specified,  only  RADs  that  have
       processes  bound to them will be returned in radset.  When
       specified, only RADs that do not have processes  bound  to
       them will be returned in radset.

RETURN VALUES    [Toc]    [Back]

       Success.   Failure. In this case, errno is set to indicate
       the error.

ERRORS    [Toc]    [Back]

       If the nloc() function fails, it sets errno to one of  the
       following  values  for the reason specified: The numa_attr
       argument (or its nattr_descr field) or the radset argument
       point to an invalid address.  One or more of the following
       conditions are true: The numa_attr  argument  contains  an
       undefined  type  value.  The nattr_descr field contains an
       invalid  resource  value  for  the  specified  type.   The
       nattr_distance or nattr_flags fields contain an invalid or
       undefined value.  The process specified by rd_pid does not
       exist.   There are too many symbolic links in rd_pathname.
       The rd_pathname length exceeds MAXPATHLEN, or a  component
       of  rd_pathname  exceeds  MAXNAMELEN.   The  file named by
       rd_pathname does not exist.  A component of rd_pathname is
       not a directory.

SEE ALSO    [Toc]    [Back]

       Functions: rad_get_info(3)

       Files: numa_types(4)



                                                          nloc(3)