OpenMP ARB Releases Public Comment Draft of OpenMP 6.1

BEAVERTON, Ore.--(BUSINESS WIRE)--The OpenMP® Architecture Review Board (ARB) has released OpenMP Technical Report 15: version 6.1 Public Comment Draft of the OpenMP Application Programming Interface (API) specification, which is expected to be released shortly before SC26 in November 2026.

The Technical Report brings substantial advancements to the OpenMP API ecosystem. First, it defines multidimensional execution spaces, enabling grid-based programming devices. Support for dynamic-lifetime data is introduced with the dyn_groupprivate clause and corresponding API routines, allowing use of fast memory for such data. The draft features new loop transformations, providing better control over data locality on devices. Thread‑affinity controls have been expanded to further optimize parallel execution.

New features included in the Public Comment Draft

The key features added in Technical Report 15 include:

• Multidimensional execution spaces: Extensions to existing parallel constructs and a set of new multidimensional routines enable a grid-based view of OpenMP teams on a device.
• 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 corresponding supplementary API routines.
• More loop transformations:
  • Coalescing of multiple nested loops into a single loop with the new flatten directive.
  • Fusing of all loops up to a specified depth using the fuse directive with the depth clause.
  • 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.
• Expanded thread‑affinity controls:
  • Extensions to OMP_PLACES express hierarchical place groups and reserve structured places.
  • Spread-affinity behavior operates over this hierarchy.
  • Enhancements to OMP_PROC_BIND with the reset and noreset modifiers control whether a thread’s original affinity is restored after a parallel region.
• 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_get_device_distances routine was added to guide device selection for device constructs. 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.

Technical Report 15 is a major milestone on the path to OpenMP API 6.1. Implementers and users are encouraged to review the document and send feedback on the proposed API to [e-mail].

Looking toward OpenMP 6.1

“OpenMP API version 6.1 adds support for multi-dimensional execution spaces,” said Michael Klemm, OpenMP ARB, CEO. “This provides the first step toward a grid-based programming style akin to CUDA and HIP, and this and other extensions provide further ways to express performance optimizations directly within the framework of the OpenMP API.”

“TR15 is the final preview release of OpenMP 6.1. It presents the proposed enhancements and clarifications that will be officially adopted when the next version is released in November,” said Bronis R. de Supinski, the Chair of the OpenMP Language Committee. “While this version is a minor release, it will include several improvements to existing features such as the device model and support for affinity control. This Technical Report represents the final opportunity to comment, so we are actively encouraging feedback.”

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.