6.5.2. Process Sets

A PMIx process set is a label associated with a fixed collection of application processes, assigned by the host environment or by the user at time of application submission. Unlike a process group, a set is immutable and confers no operational function — it is purely a label by which an application can derive information about a process and its application (see the Overview for the full comparison). This page describes the attributes used to query and report process sets.

6.5.2.1. Process Set Attributes

Several attributes are provided for querying the system regarding process sets using the PMIx_Query_info API. These include the following:

PMIX_QUERY_NUM_PSETS * String: pmix.qry.psetnum * Type: size_t * Description: Return the number of process sets defined in the specified range (defaults to PMIX_RANGE_SESSION).
PMIX_QUERY_PSET_NAMES * String: pmix.qry.psets * Type: pmix_data_array_t* * Description: Return a pmix_data_array_t containing an array of strings of the process set names defined in the specified range (defaults to PMIX_RANGE_SESSION).
PMIX_QUERY_PSET_MEMBERSHIP * String: pmix.qry.pmems * Type: pmix_data_array_t* * Description: Return an array of pmix_proc_t containing the members of the specified process set.

In addition, the PMIX_PROCESS_SET_DEFINE event shall include the name of the newly defined process set and its members using the following attributes:

PMIX_PSET_NAME * String: pmix.pset.nm * Type: char* * Description: The name of the newly defined process set.
PMIX_PSET_MEMBERS * String: pmix.pset.mems * Type: pmix_data_array_t* * Description: An array of pmix_proc_t containing the members of the newly defined process set.

Finally, a process can request (via PMIx_Get) the process sets to which a given process (including itself) belongs using the following attribute:

PMIX_PSET_NAMES * String: pmix.pset.nms * Type: pmix_data_array_t* * Description: Returns an array of char* string names of the process sets in which the given process is a member.