By Damien Lebrun-Grandie, Christian Trott, and Luc Berger-Vergiat, Kokkos Project Leads
The Kokkos team is proud to announce the release of Kokkos 5.0!
While our releases follow a steady, time-based cadence (shipping every four months), version 5.0 represents a pivotal moment in our roadmap. It marks a decisive step forward in modernization by adopting C++20 as our minimum standard, and it serves as a capstone to the highly successful 4.x series—an era that saw Kokkos solidify its place at the heart of the Exascale ecosystem.
The Move to C++20
The primary driver for the major version bump is the shift in our foundational requirements. With Kokkos 5.0, we have moved our minimum C++ standard requirement from C++17 to C++20.
Commensurate with this shift, we have raised the minimum requirements for all supported compilers and toolchains. This evolution ensures that Kokkos can leverage the expressive power and performance features of modern C++ while maintaining the portability that is central to our mission.
Key technical updates in 5.0 include:
- Modern Standards: Full adoption of C++20 and complete rewrite of Kokkos’s data structure support leveraging ISO C++ mdspan.
- Future-Proofing: Initial support for C++20 Modules, paving the way for faster build times and better encapsulation in future workflows.
- Code Hygiene: In anticipation of their eventual removal, previously deprecated code has now been disabled by default. This “spring cleaning” keeps the codebase lean and performant.
Community Engagement: A Record Turnout
Consistent communication with our user base is vital. As is our tradition following minor releases since version 3.6, we held a Kokkos Release Briefing to walk through changes introduced since version 4.7.
We were thrilled to see a record attendance of 116 participants calling in. The engagement from the community—ranging from deep-dive technical questions to roadmap discussions—highlights the growing reliance on Kokkos across the HPC landscape.
Reflecting on the 4.x Era
As we inaugurate the 5.0 series, it is worth reflecting on the milestones achieved during the lifecycle of the 4.x series. It was a period of rapid maturation and deployment for the project:
- Exascale Deployment: The 4.x series powered applications on the world’s first Exascale machines, seeing successful deployment on Aurora (Argonne National Laboratory) and El Capitan (Lawrence Livermore National Laboratory).
- HPSF Membership: During this period, Kokkos joined the High Performance Software Foundation (HPSF) at the “Established” project level, reinforcing our commitment to open governance and long-term sustainability.
- Team Expansion: We saw the CEA (French Alternative Energies and Atomic Energy Commission) team ramp up their contributions, broadening our international collaboration and development bandwidth.
- User Growth: The Kokkos user community has grown rapidly with hundreds of projects relying on the project for performance portability, and the size of its Slack community more than doubling to 2.5k developers.
Looking Ahead
Kokkos 5.0 is now available for download. We invite the community to explore the new features, update their toolchains, and continue building the next generation of portable, high-performance scientific applications.
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