Technical Report 14 is a preview of OpenMP 6.1

Beaverton, Oregon – November 13, 2023 – The OpenMP® Architecture Review Board (ARB) has released Technical Report 14, the preview of version 6.1 of the OpenMP Application Programming Interface (API) Specification, which will be released in November 2026.

This version adds new features to the loop transformation directives, such as the flatten directive, the depth clause for the fuse directive, and the sizes selector for the sizes clause to specify the number of tiles. For more control over pointer attachment in map clauses, the attach modifier was added. See the Technical Report here.

New Features included in the Technical Report:

  • More loop control: Coalesce multiple loops of a loop nest into a single loop with the new flatten directive. Fuse all loops up to a specified depth using the fuse directive with the new depth clause.
  • Support for dynamic-lifetime data: The use of small, fast memory on devices for data with dynamic lifetimes is supported with the addition of the dyn_groupprivate clause and the supplementary API routines.
  • New modifiers to improve loop transformations: The sizes modifier was added to the sizes clause to specify the number of tiles.
  • More control over data locality: The attach modifier was added to the map clause to provide more control over pointer attachment for mapped data.
  • Scalable SIMD support: To support the use of scalable SIMD instructions, the scaled modifier was added to the simdlen clause.
  • Improved device selection: The omp_default_device predefined identifier was added as a mnemonic device number.
  • Improved Fortran support: Support of the begin declare_variant directive was extended to Fortran.

In addition to adding new content, the specification and Examples document were further edited for clarity and errors have been corrected.

Technical Report 14 is a key milestone on the path to the OpenMP API Specification, version 6.1. Users and implementers are encouraged to send feedback on the proposed API to [email protected].

OpenMP 6.1 planning

“We are well on track for version 6.1 of the OpenMP API Specification release for November 2026,” said Michael Klemm, CEO of the OpenMP ARB. “Version 6.1 will not only have corrections, but will also introduce new features that will improve the usefulness of the OpenMP API.”

“Our intent is for new features in Version 6.1 to have only a small implementation complexity,” stated Bronis R. de Supinski, Chair of the OpenMP Language Committee. “Our remaining focus is primarily on potential enhancements for the device interface that supports GPUs and whether they would increase that complexity excessively.”

“The OpenMP 6.0.1 Examples document represents another important milestone in helping users adopt the latest OpenMP 6.0 features with clarity and confidence,” said Swaroop Pophale, Co-chair of the Examples Subcommittee. “By illustrating modern constructs such as taskgraph and workdistribute, and improved target_data semantics, to name a few, this release bridges the gap between the OpenMP Specification and real-world application.” See the Examples document here.

About OpenMP

The OpenMP Architecture Review Board (ARB) standardizes high-level, directive-based, multi-language parallelism that is performant, productive, and portable. Jointly defined by a group of major computer hardware and software vendors and users, the OpenMP API is a portable, scalable model that gives parallel programmers a simple and flexible interface for developing parallel applications for platforms ranging from embedded systems and accelerator devices to multicore systems and shared-memory systems. The OpenMP ARB owns the OpenMP brand, oversees the OpenMP specification, and produces and approves new versions of the specification. Further information can be found at https://www.openmp.org.

Contacts

OpenMP ARB
Kathleen Mattson
[email protected]