17.1. PMIx v6.x series

This file contains all the NEWS updates for the PMIx v6.x series, in reverse chronological order.

17.1.1. 6.1.1 – xx May 2026

Detailed changes since v6.1.0:

  • Added the –enable-test-build configure option. It force-builds the test and environment-specific components - the GPU vendor components, the NVIDIA/simptest/TCP transports, the pgpu test component, and the optional-library wrappers (zlib, zlib-ng, libesmtp, MUNGE) - so they can be compile-checked on a machine that lacks the supporting hardware or libraries. Components that need a third-party header supply a non-functional shim header used under the resulting PMIX_TESTBUILD macro. The option is intended for developers and CI: the shimmed components are not functional, so a test-build must not be installed for real use

  • Revived the pnet/simptest test fabric component. It had grown stale (its module signatures and internal node struct no longer matched the pnet interface) and no longer compiled; it has been ported to the current interface and once again drives the static endpoint/coordinate assignment path end-to-end. Fabric endpoints are delivered as per-proc data and fabric coordinates as per-node info, matching how PMIx_Get resolves each

  • PMIx_Load_topology no longer leaks the source string. When the caller does not request a specific source, the returned topology’s source field now points to a read-only, statically allocated string instead of a heap copy the caller had no safe way to release (the returned topology is shared, library-managed state that must not be destructed by the caller). A source the caller did supply remains theirs to free. The PMIx_Load_topology man page documents this ownership split

  • Group construct fault handling. When a member is lost before contributing to a PMIx_Group_construct, the server now consults the PMIX_GROUP_FT_COLLECTIVE directive (previously ignored): by default the construct aborts with PMIX_GROUP_CONSTRUCT_ABORT rather than silently forming a reduced group, while with the directive set it completes on the survivors and notifies each of them via a PMIX_GROUP_MEMBER_FAILED event naming the lost member. The server synthesizes PMIX_GROUP_MEMBER_FAILED itself, so this works with any host environment

  • Group destruct fault handling. When a member is lost before contributing to a PMIx_Group_destruct, the server now consults the PMIX_GROUP_NOTIFY_TERMINATION directive (previously ignored, so the documented behavior never occurred): by default the teardown completes on the survivors but is reported as an error, while with the directive set each survivor receives a PMIX_GROUP_MEMBER_FAILED event naming the lost member and the destruct returns PMIX_SUCCESS - the event serving in place of an error. The directive is supplied at construct time but governs the destruct; the library remembers it and re-applies it automatically (it may also be passed directly to PMIx_Group_destruct)

  • Group leader failure. A process that accepts an invitation with PMIx_Group_join_nb now watches the group leader; if the leader terminates before the construct completes, the library delivers a PMIX_GROUP_LEADER_FAILED event to the waiting process (naming the leader) so the application can drive reselection, rather than blocking indefinitely

  • Group construct timeout. A PMIX_TIMEOUT supplied to PMIx_Group_construct is now enforced by the server for the local phase: if a live participant never contributes, the construct completes with PMIX_ERR_TIMEOUT instead of hanging

  • Added the PMIX_GROUP_CANCEL group operation (a host callback used to abort an in-flight cross-server construct) and the PMIX_CAP_GROUP_FT capability flag advertising the group fault-tolerance feature set

  • PMIx_Group_leave / PMIx_Group_leave_nb are now implemented. Previously the client sent a command the server never handled, so the call returned PMIX_ERR_NOT_SUPPORTED and the documented PMIX_GROUP_LEFT event was never generated. A voluntary leave now generates a PMIX_GROUP_LEFT event notifying the remaining members of the caller’s departure (returning success once the event is locally generated, per the API contract), updates group membership on the members and in the host environment, and completes any in-flight group construct/destruct collective on the survivors rather than hanging

  • Resolve a status-code value collision: PMIX_ERR_LOST_PRECISION and PMIX_ERR_CHANGE_SIGN shared the values -400 and -401 with the PMIX_ERR_PROC_KILLED_BY_CMD and PMIX_ERR_PROC_FAILED_TO_START event codes, making the two indistinguishable to event handlers, status comparisons, and PMIx_Error_string. The two conversion-error codes have been renumbered to -202 and -203

  • gds/shmem2: make fixed-address segment attach reliable, fixing an intermittent spawn-time PMIx_Init failure (PMIX_ERR_PACK_MISMATCH) seen under AddressSanitizer and during MPI_Comm_spawn

  • gds: when a client cannot attach a gds/shmem2 fixed-address segment at runtime, it now gracefully falls back to the next available GDS module (typically hash) and re-requests its job data, instead of failing PMIx_Init. GDS module selection is now tracked per-client rather than per-namespace, so one client falling back does not affect its peers

  • plog/stdfd: implement the output-formatting directives for the stdout/stderr log channels. PMIx_Log requests that carry PMIX_LOG_TAG_OUTPUT, PMIX_LOG_TIMESTAMP_OUTPUT, and/or PMIX_LOG_XML_OUTPUT now have their output tagged, timestamped, and/or wrapped in XML, matching the formatting used for forwarded stdio. These directives were previously accepted but silently ignored

  • iof: fix XML output escaping. An ampersand was emitted as the invalid entity “≈” instead of “&”, and each escaped character left a trailing zero byte in the output due to an allocation-size overcount. This affected all XML-formatted stdout/stderr output

  • plog/smtp: fix the “body_suffix” MCA parameter, which was mistakenly registered under the name “body_prefix” and so could not be set

17.1.2. 6.0.0 – TBD

Important

This is the first release in the v6 family. The intent for this series is to provide regular “reference tags”, effectively serving as milestones for any development that might occur after the project achieved a stable landing zone at the conclusion of the v5 series. It is expected, therefore, that releases shall be infrequent and rare occurrences, primarily driven by the completion of some significant feature or some particularly critical bug fix.

For this initial release, that feature is completion of the Group family of APIs. This includes support for all three of the group construction modes, including the new “bootstrap” method. A description of each mode can be found in the Group Construction section of the documentation.

A few notes:

(1) Proper execution of the various group construction modes requires that the host provide the necessary backend support. Please check with your host provider to ensure it is available, or feel free to use the PMIx Reference RunTime Environment (PRRTE) - you will require v4.0 or above.

(2) Starting with this release, PMIx requires Python >= v3.7 to build a Git clone (ie., not a tarball). Certain elements of the code base are constructed at build time, with the construction performed by Python script. The constructed elements are included in release tarballs.

(3) PRRTE < v4.0 is not compatible with PMIx >= v6.0 due to internal changes (e.g., show-help messages are now contained in memory instead of on-disk files).

A full list of individual changes will not be provided here, but will commence with the v6.0.1 release.