Utilising cycle-accurate architectural simulation to aid in the design space exploration of future HPC hardware.

The domain of high performance computing (HPC) aims to increase the feasibility of solving large, computationally-intense problems. Within this domain, high performance hardware is aggregated in such a way as to extract high levels of computational power unattainable by simple desktop computers; it is these approaches that enable HPC's aim. Both the techniques used to deliver high performance from computer architecture and, undoubtedly, the hardware itself need to be developed to maintain the performance advancement required by applications in HPC. To aid the development of high performance architectures, designers must be able to conduct studies to explore the design space and determine the impact of changes made. However, with the increasing complexity in HPC trends this space is expanding, which in turn, reduces the feasibility of these studies. There is a need to mitigate this complexity as to re-introduce the feasibility of potential gains.

There is a wide range of applications seen to utilise the gains of HPC. Simulation and modelling are such applications and are of substantial importance to both modern science and engineering, they shift experimentation from the physical to the digital domain allowing for faster and more numerous investigation. ASiMoV, a EPSRC prosperity partnership, is a project that involves one such application with the focus on achieving "the world's first high fidelity simulation of a complete gas-turbine engine during operation''. As accurately stated by the project, "This level of simulation will require breakthroughs at all levels'' one of which being "Exascale HPC hardware''.

The University of Bristol's HPC group is one of the contributors towards the ASiMoV project providing its academic expertise in advanced computer architecture to help solve the problems stated in ASiMoV. Amongst other contributions, they are currently developing an architectural simulator called the Simulation Engine (SimEng) framework to enable processor design space exploration.

I aim to begin my research by aiding the University of Bristol's HPC group's contribution to the ASiMoV project through the continued development of SimEng whilst maintaining the focus on its primary goals, to be fast, accurate and easy to modify. I shall also be assessing whether the simulation framework could combat the complexity in HPC trends during exploration and whether it could identify architectural changes to support the advancement to Exascale Computing.

SimEng is not the only architectural simulator. Many exist and in theory any of these could be used to address the aforementioned key issues in design space exploration. However, as stated in the ModSim 2019 presentation given by Simon McIntosh-Smith and with the focus on the ASiMoV project, the combination of speed and accuracy provided by these simulators aren't at the level needed for addressing exascale hardware design analysis. Thus, SimEng was devised to investigate these research questions.

SimEng's involvement in the ASiMoV project offers the opportunity to work on motivated science use-cases namely. Beyond this, the challenges tackled within the project are repeated across many disciplines that are in need of simulation and modelling techniques to a similar fidelity, thus, the developments made have beneficial impacts outside the specific context of ASiMoV. Due to the University of Bristol's HPC group's strong industrial links, there are partnerships with ARM, Fujitsu and Marvell to explore future computer architecture design space aiding both the development of the simulation framework and the understanding of its impact within the industrial domain.

The evolution of this simulation framework would help validate the feasible gains of possible architectural alterations whilst also enabling efficient and rigorous exploration with fast execution and flexible architectural modification respectively.

This project falls within the EPSRC Information and communi