Alexander Kropotov

Noelia Oliete-Escuín, Arnau Bigas, Narcís Rodas et al.

Chip industry continues advancing and expanding modern computing systems, resulting in more complex multi-core processors. Conversely, academic projects face scalability challenges due to limited resources, highlighting the need for open-source frameworks that enable innovation and knowledge sharing. Recently, several open-source proposals have emerged, offering flexible and scalable designs, but fail to meet the performance demands of modern High-Performance Computing (HPC) applications. In this project, we present REPTILES, an open-source RISC-V multicore framework based on OpenPiton\thanks. REPTILES interconnects multiple Sargantana cores with the memory hierarchy of OpenPiton. Moreover, we present the new features incorporated in Sargantana and OpenPiton designs to improve the performance of HPC applications. We demonstrate that REPTILES presents suitable scalability, achieving a speedup of 3.1x on average with 4 cores. Additionally, we show that Sargantana's new features increase the performance of vector addition benchmark in a 9.3x.

Alexander Kropotov, Miquel Moreto, Behzad Salami

FPGA-level emulation is a key step in pre-silicon chip design validation. However, emulating large-scale multi-core systems increasingly exceed the hardware resource capacity of a single FPGA, limiting the feasibility of full-system emulation. To address this challenge, we introduce EMiX, a scalable multi-FPGA framework that enables distributed emulation of multi-core RISC-V architectures beyond single-FPGA resource limits. EMiX systematically partitions a monolithic multi-core design into multiple components and deploys them across multiple interconnected FPGAs, effectively exploiting inter-FPGA interconnects to balance scalability and performance without requiring fundamental RTL redesign. We prototype EMiX with a 64-core architecture across eight interconnected Alveo U55c FPGAs (scalable on core and FPGA counts), successfully demonstrating full-system execution including Linux boot. EMiX will be released as an open-source platform.

Sajjad Ahmed, Alexander Kropotov, Roberto Ignacio Genovese et al.

The Barcelona Zetascale Lab (BZL) project aims to strengthening Europe's capacity in the design and manufacture of RISC-V based high-performance computing chips. In this context, we present a holistic pre-silicon verification and validation (V&V) methodology targeting highly robust RISC-V chip designs. This paper provides an overview of BZL's V&V approach, which integrates three complementary platforms: (1) a UVM-based verification environment to thoroughly validate RTL functionality; (2) an FPGA-based validation platform that enables system-level pre-silicon hardware-software RTL validation; and (3) a CI/CD flow that continuously automates build, deployment, and tests across these domains. By embedding these platforms into an industrial-grade V&V loop and exploiting large-scale CPU and FPGA hardware infrastructures, the BZL project enables continuous evolution of reliable hardware development and software integration. We believe that the BZL's V&V flow represents a robust and scalable foundation for ensuring the pre-silicon functional correctness and system level validation of RISC-V chip designs, and can serve as a key enabler for strategic initiatives in Europe, such as EPI and DARE, and beyond.