EUPEX Pilot aims to demonstrate Europe’s capability to build ARM-based systems and a software stack designed for diverse European HPC requirements

The ability to build and operate powerful supercomputers is now a key factor shaping technological independence and Europe’s position on the global stage. As major investments continue to flow from the United States and Asia, Europe faces a growing challenge: developing its own technologies while remaining competitive at the highest level.

EUPEX, a European project funded by the EuroHPC Joint Undertaking, directly addresses this challenge by developing a pilot supercomputing platform entirely based on European technologies, from the hardware to the software stack. The platform will use new ARM-based processors designed for the performance, energy efficiency, and scalability needed in next-generation HPC systems, offering a tangible step toward Europe’s computing independence.

The pilot will assemble these processors within a modular architecture and couple them with European-developed software solutions, providing a realistic environment to test readiness, scalability, and operational reliability. In doing so, EUPEX Pilot aims not only to prove that Europe can deliver competitive, high-performance supercomputing infrastructures, but also to develop and demonstrate European expertise in microelectronics, system architecture, and HPC software. The project also explicitly prepares applications and European users to efficiently exploit future Exascale machines, providing opportunities for co-design and early testing of workflows and software on the new platform.

Bringing together leading European research centres, technology providers, and industrial partners, EUPEX Pilot sets the stage for the next era of European supercomputers, showing that a fully European stack can operate at scale and paving the way for larger, sovereign HPC systems.

The EUPEX Consortium

At the heart of this ambition is a diverse and strategically balanced consortium of 17 European organisations, each contributing unique expertise to the challenge of building a fully European HPC ecosystem. The consortium includes established technology suppliers, research institutions, national supercomputing centres, industrial innovators, and application stakeholders. Coordinated by Eviden, these partners ensure that research and development efforts translate into industrialised solutions based on European technologies. Key members include: Forschungszentrum Jülich, CEA, GENCI, Cineca, E4 Computer Engineering, ParTec, EXAPSYS, SECO, CybeleTech, ECMWF, Politecnico di Milano / CINI, University of Mainz, IT4Innovations, University of Zagreb, and other leading academic institutions. Together, they form a European ecosystem of expertise that underpins the technical and strategic objectives of EUPEX Pilot.

The EUPEX Pilot System

The EUPEX Pilot System is built around a hardware-software co-design approach aimed at delivering a modular and flexible European HPC platform. It is designed to integrate the expertise of the consortium into a coherent system capable of addressing the requirements of current and emerging scientific applications.

On the hardware side, the platform follows the Modular Supercomputing Architecture (MSA) paradigm, enabling heterogeneous computing resources to be combined within a single system. This modular design provides the flexibility to integrate different technologies as they become available. The EUPEX system is focused on deploying an ARM-based pilot platform at production-class scale. This system is used as a testbed for the integration of European-designed processors, including the Rhea chip developed by SiPearl as part of the European Processor Initiative (EPI). Running these technologies under realistic system conditions allows the project to assess performance, energy efficiency, and integration challenges in a controlled but representative HPC environment.

The EUPEX Pilot also places strong emphasis on the software stack, which is a decisive element for the effective exploitation of modular, ARM-based HPC systems. Beyond performance considerations, the project addresses a strategic requirement: the availability of a European software ecosystem that does not rely on non-European technologies. For a number of scientific, industrial, and institutional users, HPC systems support highly sensitive and strategic activities, making software independence, security, and long-term control essential. EUPEX therefore aims to define and deploy a software environment fully aligned with European technologies and practices. The EUPEX software ecosystem is designed to support both application developers and system operators while addressing the requirements of key applications identified within the project.

The EUPEX Pilot System is designed as a proof-of-concept at meaningful scale. Its architecture is sufficient to evaluate applications, workflows, and system software in conditions close to production.

Selected applications were co-designed and deployed to test scalability, performance, and energy efficiency on ARM-based European hardware. Beyond technical validation, the Pilot provides a shared environment for European research teams and application owners, offering early access to new hardware technologies and concrete feedback for future system designs.

EUPEX started with a strong hardware focus. Can you remind us of this initial vision and how the project naturally shifted toward software?

EUPEX started with a plan to have a strong emphasis on hardware-driven system development, focusing on integrating European innovations across hardware (such as the European processor), system architecture (the MSA approach from the DEEP projects), and software components originating from multiple initiatives like DEEP and IO-SEA. However, as the project progressed, it became increasingly clear that software would play a decisive role in determining the overall impact of EUPEX, particularly in terms of system usability and the breadth of stakeholder engagement.

In a complex initiative like EUPEX, hardware availability can be subject to long and uncertain timelines, making it difficult to rely solely on system-level integration at later stages. By contrast, having clearly defined system software, interfaces, and environments available early significantly improves accessibility and usability once the hardware becomes operational. In this sense, software has become a stabilising factor – providing continuity and enabling progress even when hardware timelines were uncertain. This realisation led to a shift in priorities toward developing a well-defined, integrated software stack early in the project lifecycle.

Moreover, the project has recognised that a fully functional EUPEX system cannot exist without the tight interplay of its software components, spanning system management, execution environments, performance optimisation, and storage/I/O. Each of these layers is critical, and the absence of any one of them would prevent the realisation of a complete MSA system. This has reinforced a vision where software is not just complementary but foundational, shaping EUPEX’s priorities toward integration, readiness, and delivering a cohesive, usable HPC platform from the outset.

EUPEX has been developing and integrating the EUPEX Software Stack within its pilot platform. What does it include, and how do these different elements fit within the system?

The EUPEX Software Stack is a comprehensive, layered ecosystem spanning all levels of a cutting-edge HPC system. It includes components for MSA-aware system management components, including system control and provisioning, execution environments, performance tuning, monitoring, energy management, and a full I/O stack.

The system management portion of the stack primarily includes OCEAN and ParaStation Modulo software components to efficiently manage and orchestrate the EUPEX MSA system. It also includes tools for trusted execution and monitoring.

The Execution environment portion of the stack allows for allows for flexible and efficient utilisation of resources within the Modular system for both users and system operators. They include MPI flavours (ParaStation MPI, Open MPI, GPI-2) and tools such as ACCO and BHCO for performance tuning in this context. The Execution environment also includes tools such as Streamflow dealing with workflow orchestration, and tools such as HWLoc and VHC allowing for the exploitation of hardware capabilities.

The performance tuning and energy efficiency portion of the stack includes tools for energy monitoring and power management (eg: EO), energy efficiency-focused tools (eg: MERIC AND COUNTDOWN) and performance monitoring and performance data collection tools (eg: SCORE-P, Parastation Management).

The storage and I/O portion of the stack deals with components that focus on the in-memory tiers (eg: CAPIO, DAMARIS), high-performance tiers such as Flash (eg: software from the IO-SEA Project, a distributed KV Store, memory-mapped I/O components), application-specific interfaces derived from climate/weather applications and  tools for I/O and storage acceleration (eg: IO-SEA instrumentation and ParaStation Health Checker).

What makes the EUPEX stack distinctive is how these components are actively integrated rather than developed in isolation. They are developed and ported together in a strict co-design approach, interacting closely with applications and the continued development of the Pilot.

Could you highlight a few key tools developed within EUPEX that showcase the scope of the Software Stack?

EUPEX has developed and integrated a wide range of tools that demonstrate the breadth and depth of the software stack. At the system level, Ocean serves as the central provisioning and integration framework, acting as the entry point for assembling and deploying the full software environment, while ParaStation Modulo provides cluster management, resource scheduling, and MPI runtime capabilities tightly integrated into the control plane. Together, these tools illustrate how EUPEX addresses system-level orchestration and management in a modular supercomputing context.

At the execution and performance level, several tools highlight innovation in scalability and efficiency. For example, ParaStation MPI with RRComm introduces a new communication mechanism that removes traditional bottlenecks in MPI initialisation, improving scalability for large systems. Tools like ACCO (for performance tuning), libVC (for runtime code optimisation), and StreamFlow (for workflow orchestration across HPC and cloud environments) demonstrate how EUPEX supports dynamic, heterogeneous workloads. In addition, monitoring and energy tools such as LLview and MERIC/COUNTDOWN provide insights into performance and power consumption, enabling optimisation at runtime.

Finally, in the area of storage and I/O, solutions such as CAPIO, DAMARIS, and the IO-SEA stack, as well as specialised components like Fennec, a secure key-value store using trusted execution environments showcase EUPEX’s focus on data-intensive workloads, security, and efficient data movement, which are critical for exascale systems. In this area, tools such as Bull Sequana ARGOS is designed to give insights not just into I/O-related metrics but also in the provision of granular, near real-time monitoring of HPC jobs and captures a wide array of performance and energy-related metrics.

Together, these examples illustrate that the EUPEX Software Stack is not just a collection of tools, but a fully integrated environment covering system management, execution, optimisation, and data handling for next-generation HPC platforms.

What are the current and future plans for making the EUPEX Software Stack accessible beyond the consortium, and what challenges do you face in this process?

Ensuring broad user adoption and long-term exploitation of the EUPEX Software Stack is a key priority, not only during the project lifetime but also beyond its completion. To support this, EUPEX has established an Early Access Programme (EAP) very early on, aimed at building a community of users around EUPEX software components and tools and best practices, while actively collecting user feedback – providing external users access to computing resources that would be similar to the eventual EUPEX Pilot. This early engagement is critical to ensuring that the software evolves in line with user needs and is ready for broader adoption after the project ends.

To ensure wider availability and sustainability, EUPEX is also working on assessing and aligning with established European software distribution ecosystems. This includes leveraging repositories such as OCEAN Forge for integration and deployment of system software, and/or exploring initiatives like EESSI to distribute open-source software in a portable and reproducible manner across HPC environments. By relying on such well-known and widely adopted platforms, EUPEX aims to make its software stack accessible to a broader community beyond the immediate project infrastructure, while also ensuring long-term maintainability and reuse.

However, several challenges remain. The software stack is composed of multiple components developed by different partners, and while individual tools may already have established user bases, integrating them into a coherent and discoverable ecosystem is non-trivial. Additionally, dissemination and exploitation often occur through the individual channels of project partners, which can lead to fragmentation and limited awareness of the full EUPEX offering. Addressing these challenges will require stronger coordination, clearer integration pathways, and more unified communication strategies to ensure that the EUPEX Software Stack is perceived and adopted as a complete, interoperable solution. The different licensing terms of the various software components (spanning from open source to proprietary licenses) also poses another challenge. EUPEX has a dedicated Software Steering Group focussed on these issues.

How do you plan to bring visibility to the EUPEX Software Stack within the broader HPC community, and what initiatives or events are planned in this direction?

The plan to increase visibility of the EUPEX Software Stack within the HPC community is centred on active participation in major international events and targeted dissemination activities. Key conferences such as ISC (International Supercomputing Conference) 2026, Euro-Par (International European Conference on Parallel and Distributed Computing) 2026, and SBAC-PAD (IEEE/SBC International Symposium on Computer Architecture and High Performance Computing) 2026 will serve as primary events to showcase EUPEX technologies. At these venues, the project will leverage booths, poster sessions, and workshop opportunities to demonstrate software tools and engage external users and stakeholders. In particular, we will have presence at ISC through a shared booth.

A flagship initiative is the organisation of a dedicated mini-symposium at Euro-Par 2026, which has already been accepted and will act as a focal point for presenting the EUPEX Software Stack. This event will include presentations, posters, and discussions specifically tailored to highlight project software outcomes and foster dialogue with the research community.

Beyond conferences, the visibility strategy includes a strong communication and publication component. This involves continuing to produce high-quality scientific papers in leading journals/conferences and also preparing a flagship paper on EUPEX technologies. Additionally, branding efforts around the EUPEX software, and launching further webinars focused on software are ongoing.

Engaging the HPC community

As EUPEX enters its final phase, dissemination and community engagement are becoming central, with a strong focus on the EUPEX Software Stack. The project aims not only to deliver a pilot system, but also to share its results, tools, and experience with the European HPC community.

A key initiative is the Early Access Program (EAP), which provides selected organisations – including EuroHPC Centres of Excellence, EU-funded projects, and other stakeholders – with access to the EUPEX platform. Users can experiment with a Grace-based partition together with the EUPEX Software Stack, gaining early hands-on experience with emerging European technologies.

Beyond platform access, EUPEX places strong emphasis on sharing lessons learned. While some hardware objectives have evolved, the project has delivered substantial results on the software and application side, including ARM porting, co-design activities, and the development of tools for system administration, performance optimisation, and workflow management. These efforts help prepare the HPC community for future European systems.

To support this, EUPEX researchers organise regular webinars presenting concrete results and tools developed within the project. Additional sessions are planned, and the full webinar schedule is available on the project website. All past webinars can also be accessed there as replays on YouTube. Topics include:

• Advances in geospatial foundation models for earth observation: Scaling machine learning with supercomputing on large remote sensing datasets.
• Bolt65 – AI fusion: A case study in object detection using AI techniques on HPC systems.
• OpenGADGET: HPC highlights from cosmological simulations: Challenges and insights from large-scale simulations of the Universe.
• Scientific workflows in the heterogeneous era (StreamFlow): Managing complex workflows across heterogeneous computing environments.
• Vectorisation of FEM kernels (ESPRESO FEM): Optimising finite element kernels for modern HPC architectures.
• ParaStation Modulo – Managing system heterogeneity at scale: Tools and methods to operate heterogeneous HPC systems efficiently.
• A practical approach to OCEAN: CEA’s admin software stack for HPC clusters: Experience feedback on HPC system administration and software management.
• Manual and automated optimisation techniques for the Integrated Forecasting System: Performance optimisation strategies for numerical weather prediction.
• Flexibilities of wavelets in BigDFT: Wavelet-based methods as a computational basis set for large-scale electronic structure calculations.

EUPEX also engages with the community through workshops and tutorials at major European HPC conferences such as ISC and Euro-Par, one of the leading scientific conferences in parallel and distributed computing.

At Euro-Par, EUPEX will organise a dedicated mini-symposium focused on the EUPEX Software Stack. This session will bring together presentations, posters, and technical discussions to provide a comprehensive overview of the stack’s architecture, key components, and current capabilities. It will highlight concrete results from the project, including software developments and co-design activities, while offering participants the opportunity to interact directly with developers and explore potential use cases within the European HPC ecosystem.

EUPEX will also be present at ISC, offering further opportunities to connect with the team and explore the project’s latest developments. Participants are invited to meet the EUPEX team and learn more about its technologies at these events.

 

This project has received funding from the European High-Performance Computing Joint Undertaking (JU) under grant agreement No 101033975. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and France, Germany, Italy, Greece, United Kingdom, Czech Republic, Croatia.

Please note, this article will also appear in our upcoming High-Performance Computing Special Focus publication.