About the job

Flux Computing is seeking a Performance Modelling Engineer to design and own analytical and simulation models that shape the evolution of its Optical Tensor Processing Unit (OTPU) architecture and software. In this role, you will develop both functional and cycle-accurate simulators, conduct workload analysis, identify bottlenecks, and run large-scale design-space explorations to deliver insights that directly influence hardware, software, and optical roadmaps. You will collaborate closely with cross-disciplinary teams, champion modelling methodologies, and drive a culture of data-driven design across the company. The ideal candidate will have 7+ years of experience building performance or power models for CPUs, GPUs, ASICs, or accelerators, strong proficiency in C++ and Python, and hands-on experience with discrete-event or cycle-accurate simulators such as gem5 or SystemC. A deep understanding of computer architecture fundamentals, including memory systems, interconnects, queuing theory, and performance analysis, is required, along with familiarity in machine learning workloads (PyTorch, TensorFlow, JAX). Additional strengths include the ability to interpret RTL, excellent data-visualisation and communication skills, and a proven record of technical leadership. This role offers a competitive salary with stock options, a unique location bonus of up to £24,000 for living near the King’s Cross HQ in London, visa sponsorship with full relocation support, BUPA healthcare and dental coverage, high-spec tech setups, chef-cooked meals, pension plans, and other lifestyle benefits.