Enhancing Interoperability in Task-based Programming Models through Common Low-Level Interfaces

Research topic and goals

Task-based programming models are a promising approach to exploiting complex distributed and heterogeneous systems. Recently, these models have emerged as a viable alternative to traditional message-passing and fork-join approaches, reflecting the research community’s growing interest in their numerous benefits. Despite these advantages, the broader adoption within the scientific and industrial sectors remains limited. A major barrier is the poor interoperability among existing runtime systems, which prevents the development of complex applications through the integration of multiple components or libraries written in different task-based programming models. Such interoperability issues often lead to oversubscription, significantly impairing applications’ performance. Maintainability presents another significant challenge within task-based programming models, encountered by projects at varying stages. The relatively modest level of effort anticipated in a future steady-state raises critical questions about the sustainability of support for these models. Can the organization of software, potentially through the utilization of shared code bases for sub-components, facilitate easier maintenance? Such an approach could potentially streamline the support process, thereby enhancing the long-term viability and operational efficiency of task-based systems.

Our project aims to address these challenges by identifying the low-level primitives necessary for building efficient and scalable task-based runtime systems. Based on these findings, we will develop unified low-level tasking interfaces to enhance interoperability among different runtime systems, optimizing performance and encouraging broader adoption of task-based programming models.

Results for 2025/2026

We have continued the monthly video call to coordinate activities and ensure continuous progress.

Main highlights for this period:

StarPU and PaRSEC ported to nOS-V. David Álvarez carried out a summer internship at Inria Bordeaux (hosted by Olivier Aumage and Thomas Hérault). During the internship, he completed the port of StarPU and PaRSEC to nOS-V, and evaluated their interoperability with OpenMP using three applications. This work was submitted as a full research paper to IPDPS, but it was not accepted.
Charm++ reconvers discussions. We discussed the new implementation of Charm++ runtime convers, called reconvers, aimed at reducing code-base complexity, addressing technical debt, and enabling a simpler design that can better leverage new high-performance communication libraries, especially in highly multithreaded environments. Charm++ already works with reconvers but there are some performance issues with large applications.
Community coordination. We plan to organize another BoF at the next JLESC workshop to align on interoperability priorities and cross-runtime collaboration.

Results for 2024/2025

Since the project’s inception in September 2024, we have established a monthly video call to coordinate activities and ensure continuous progress.

Our work is currently organized around two main objectives:

Survey and Documentation of Runtime System Components We are actively discussing and documenting key components of various runtime systems, including schedulers, dependency management, and communication libraries. This effort aims to identify commonalities and opportunities for cross-runtime interoperability. We plan to consolidate our findings into a survey paper that will highlight similarities and differences among existing runtime systems and propose reusable components that could benefit multiple implementations.
Porting StarPU and PaRSEC to nOS-V We have initiated work on adapting StarPU and PaRSEC to run on top of nOS-V. A working prototype of StarPU/nOS-V has already been developed, marking a significant milestone. To further advance this effort, we have secured a summer internship for 2025 in collaboration with Inria and BSC. This internship will focus on improving the integration and evaluating the performance of StarPU and PaRSEC within the nOS-V environment

Visits and meetings

We had a BoF session in Kobe 2024 workshop, where we decided to start this project.
We had a BoF session in Argonne 2025 workshop, where we discussed interoperability challengues.
David Álvarez completed a summer internship at Inria Bordeaux (June–August 2025), hosted by Olivier Aumage and Thomas Hérault, focused on porting StarPU and PaRSEC to nOS-V and evaluating interoperability with OpenMP.
We plan to organize another BoF at the next JLESC workshop.

Publications

David Álvarez, Olivier Aumage, Thomas Hérault, Vicenç Beltran. Efficiently combining parallel libraries and programming models in HPC applications. (to be submitted in early 2026).

Impact

Port of StarPU to nOS-V completed in 2025
Port of PaRSEC to nOS-V completed in 2025
Solve interoperability problems between task-based programming models
Increase software development productivity and reach of task-based programming models
Research and document needs from higher-level programming systems (Charm++, HPX, Legion, PaRSEC, OpenMP, OmpSs, ..) for the task-based execution systems
Explore possibility of creating a standard that allows for different use cases currently served, either via a flexible design or allowing for extensions

References

Álvarez, David, Kevin Sala, and Vicenç Beltran. 2024. “NOS-V: Co-Executing HPC Applications Using System-Wide Task Scheduling.” In IEEE International Parallel and Distributed Processing Symposium, IPDPS 2024, San Francisco, CA, USA, May 27-31, 2024, 312–24. IEEE. https://doi.org/10.1109/IPDPS57955.2024.00035.

@inproceedings{DBLP:conf/ipps/0006S024,
  author = {{\'{A}}lvarez, David and Sala, Kevin and Beltran, Vicen{\c{c}}},
  title = {nOS-V: Co-Executing {HPC} Applications Using System-Wide Task Scheduling},
  booktitle = {{IEEE} International Parallel and Distributed Processing Symposium,
                    {IPDPS} 2024, San Francisco, CA, USA, May 27-31, 2024},
  pages = {312--324},
  publisher = {{IEEE}},
  year = {2024},
  url = {https://doi.org/10.1109/IPDPS57955.2024.00035},
  doi = {10.1109/IPDPS57955.2024.00035},
  timestamp = {Wed, 17 Jul 2024 15:59:37 +0200},
  biburl = {https://dblp.org/rec/conf/ipps/0006S024.bib},
  bibsource = {dblp computer science bibliography, https://dblp.org}
}

Bosilca, George, Aurelien Bouteiller, Anthony Danalis, Thomas Herault, Pierre Lemariner, and Jack Dongarra. 2011. “DAGuE: A Generic Distributed DAG Engine for High Performance Computing.” In , 1151–58. Anchorage, Alaska, USA: IEEE.

@inproceedings{icl:675,
  title = {DAGuE: A Generic Distributed DAG Engine for High Performance Computing},
  year = {2011},
  month = {2011-00},
  pages = {1151-1158},
  publisher = {IEEE},
  address = {Anchorage, Alaska, USA},
  keywords = {dague, parsec},
  author = {Bosilca, George and Bouteiller, Aurelien and Danalis, Anthony and Herault, Thomas and Lemariner, Pierre and Dongarra, Jack}
}

10.1007/978-3-642-03869-3_80

Augonnet, Cédric, Samuel Thibault, Raymond Namyst, and Pierre-André Wacrenier. 2009. “StarPU: A Unified Platform for Task Scheduling on Heterogeneous Multicore Architectures.” In Euro-Par 2009 Parallel Processing, edited by Henk Sips, Dick Epema, and Hai-Xiang Lin, 863–74. Berlin, Heidelberg: Springer Berlin Heidelberg.
@inproceedings{10.1007/978-3-642-03869-3_80, author = {Augonnet, C{\'e}dric and Thibault, Samuel and Namyst, Raymond and Wacrenier, Pierre-Andr{\'e}}, editor = {Sips, Henk and Epema, Dick and Lin, Hai-Xiang}, title = {StarPU: A Unified Platform for Task Scheduling on Heterogeneous Multicore Architectures}, booktitle = {Euro-Par 2009 Parallel Processing}, year = {2009}, publisher = {Springer Berlin Heidelberg}, address = {Berlin, Heidelberg}, pages = {863--874}, isbn = {978-3-642-03869-3} }
In the field of HPC, the current hardware trend is to design multiprocessor architectures that feature heterogeneous technologies such as specialized coprocessors (e.g. Cell/BE SPUs) or data-parallel accelerators (e.g. GPGPUs).

Kale, L.V., M. Bhandarkar, N. Jagathesan, S. Krishnan, and J. Yelon. 1996. “Converse: an Interoperable Framework for Parallel Programming.” In Proceedings of International Conference on Parallel Processing, 212–17. https://doi.org/10.1109/IPPS.1996.508060.

@inproceedings{508060,
  author = {Kale, L.V. and Bhandarkar, M. and Jagathesan, N. and Krishnan, S. and Yelon, J.},
  booktitle = {Proceedings of International Conference on Parallel Processing},
  title = {Converse: an interoperable framework for parallel programming},
  year = {1996},
  volume = {},
  number = {},
  pages = {212-217},
  keywords = {Parallel programming;Object oriented programming;Parallel languages;Runtime},
  doi = {10.1109/IPPS.1996.508060}
}