Senior AI Performance Modeller in London

About OLIX

AI is growing faster than any technology in history and the explosion in demand has created a massive infrastructure gap; we can no longer build chips or power stations fast enough to keep up. The industry is still leaning on a ten-year-old hardware blueprint that has reached its limit. A new paradigm that is faster and more efficient will be the biggest economic opportunity of the next century and create the most important company of the next decade. OLIX is building this next paradigm; the Optical Tensor Processing Unit (OTPU) achieves performance and energy efficiency that is impossible to match from existing chips.

The Role

We are searching for a Senior Performance Modelling Engineer to create and own the analytical and simulation models that steer OTPU architecture and software evolution. You will build functional simulators as well as high-fidelity, cycle-accurate models of our optical compute system. This role is critical to explore "what-if" design spaces, and deliver insights that directly influence our software, hardware, and optical roadmaps. This role sits at the crossroads of hardware architecture, software tooling and machine-learning workload analysis, perfect for an engineer who loves data-driven decision-making and fast iteration.

Responsibilities

• Project Ownership: Own and deliver projects on your team’s roadmap that unlock key high-impact technical and business milestones that drive the success of OLIX.
• Collaboration: Work shoulder-to-shoulder with hardware, compiler and ML framework teams to ensure models reflect reality and reality meets performance goals.
• Functional Simulator: Design, build, and maintain a functional simulator of the OPTU subsystem and full pipeline.
• Performance Simulator: Design and maintain architectural & cycle-accurate models of the OPTU subsystems and pipeline. Identify throughput, latency and utilisation hot-spots; propose architectural, or scheduling fixes.
• Workload Analysis & Bottleneck Hunting: Instrument benchmarks (LLMs, diffusion, graph workloads) to collect detailed traces.
• Design-Space Exploration: Run massive parameter sweeps with your functional and to understand tradeoffs and guide the software, hardware, and optical teams. Package results into clear, quantitative analyses and design recommendations.
• Tooling & Automation: Develop Python/C++ tooling for trace parsing, statistical analysis and visualisation. Integrate models into CI so that every RTL commit gets a performance smoke test.

Skills & Experience

• 5+ years building performance or power models for CPUs, GPUs, ASICs, or accelerators.
• Strong coding ability in C++ and Python; experience with discrete-event or cycle-accurate simulators (e.g., gem5, SystemC, custom in-house).
• Solid grasp of computer-architecture fundamentals: memory systems, interconnects, queuing theory, Amdahl/Gustafson analysis.
• Familiarity with machine-learning workloads and common frameworks (PyTorch, TensorFlow, JAX).
• Comfort reading RTL or schematics and discussing micro-architectural trade-offs with hardware designers.
• Excellent data-visualisation and communication skills: able to turn millions of simulation samples into one decisive slide.
• Bachelor's+ in EE, CS, Physics, Applied Maths or related; advanced degree preferred but not required.
• Personal or open-source projects in simulators, ML kernels, or performance analysis are a significant plus.

Compensation & Benefits

• Competitive Salary: £174,000+, commensurate with your experience, skills, and location.
• Equity & Ownership: Meaningful stock options. You’re not just joining the mission; you’re owning a piece of it.
• Proximity Bonus: We value your time. To minimise your commute and maximise your life, we offer a £24k annual Living-Local Bonus if your residence is within 20 minutes of the office.

Health & Wellbeing

• Premium Healthcare: Comprehensive BUPA medical and dental cover, including Medical History Disregarded (MHD), for complete peace of mind.
• Time Off: 25 days of annual leave, plus all UK public holidays.