Overview

We are looking for a CPU Performance Engineer to join our team, with a focus on understanding CPU performance on real devices and translating observations into insights that can help guide CPU architecture and microarchitecture decisions.

We work with silicon platforms and commercial devices, investigating performance in complex environments where system behaviour is not always predictable or easy to reproduce. This requires a solid understanding of CPU fundamentals, together with an interest in exploring how software and system-level behaviour interact with the underlying CPU microarchitecture.

You will work alongside experienced CPU architects and performance engineers to investigate performance bottlenecks, develop and test hypotheses, and build the evidence needed to support CPU design decisions.

While this is not a CPU design or microarchitecture role, our work directly contributes to their development. We identify and analyse performance limitations observed on devices, validate our findings using pre-silicon platforms (FPGA, emulation or performance models) when possible, and use the results to make concrete, data-backed recommendations to CPU teams.

Responsibilities

Analyse Performance on Real-World Workloads

We investigate the performance of real-world workloads running on silicon platforms and commercial devices, looking at how system-level behaviour affects CPU performance and identifying the factors that contribute to observed bottlenecks.

Our investigations often take place in complex environments with limited observability, where waveforms are unavailable, performance counters provide only partial information, and measurements can be noisy or difficult to reproduce.

CPU-Focused Performance Analysis

We use PMU counters, profiling tools and targeted experiments to understand CPU behaviour and identify performance limitations across different parts of the microarchitecture, including memory, front-end, back-end and execution.

When needed, we extend our investigations to more controlled environments, using FPGA, emulation or performance models to reproduce behaviours observed on silicon, isolate CPU-specific effects and validate hypotheses.

Where applicable, we compare results across silicon, models and emulation platforms to better understand observed differences and build confidence in our conclusions.

Influence CPU Microarchitecture

Our findings contribute to discussions with CPU architecture and build teams, providing data and analysis to help find opportunities for improving future CPU compositions.

We document investigations, communicate results and recommendations clearly, and contribute to the continuous improvement of our existing performance analysis tools and workflows.

Experience

Required Skills

We are looking for someone with:

• Good understanding of CPU microarchitecture fundamentals (pipelines, caches, speculation, memory hierarchy).
• Experience in performance analysis, including profiling, benchmarking or debugging.
• Familiarity with PMU-based profiling tools or similar performance counters.
• Basic programming and scripting skills (Python, C/C++ or similar).
• Strong analytical and problem-solving skills.

Nice to have

We would also value familiarity with:

• CPU performance analysis, benchmarking and low-level software (C/assembly).
• RTL concepts, FPGA or emulation platforms.
• Performance investigations on real devices (mobile, embedded or client).
• System-level interactions (OS, scheduling, memory).
• Arm architecture.

Profile

We are looking for someone who:

• Is curious about how real-world software and system behaviour affect CPU performance.
• Is comfortable investigating complex problems with incomplete or noisy data.
• Is eager to learn, collaborate with experienced engineers and develop their technical expertise.
• Can communicate findings clearly and support conclusions with evidence.

Additional Information

If skilled worker sponsorship is required, Arm will meet costs associated with sponsorship for the employer only. All fees associated with the individual’s application e.g. visa application fee and Immigration Health Surcharge, will be the responsibility of the successful candidate.

#LI-CI

Our 10x Mindset

At Arm, we believe progress happens when people are empowered to think bigger and push beyond what seems possible. Our 10x mindset is about curiosity, ambition and creating impact that will be used by millions. We learn fast, prioritise collaboration and turn bold ideas into real technology. We look for people who are inspired by this way of working and want to grow in an environment where bold ideas are welcomed. Discover how the 10x mindset shapes life at Arm: https://careers.arm.com/10x-mindset

Use of AI in Your Application

At Arm, we embrace the benefits AI can bring, including in recruitment. You may use AI to support your preparation, such as improving the clarity of written responses, practicing interview questions, or learning more about our industry. However, your application and interview responses must reflect your own thinking, experience, and abilities. We want to understand your authentic perspective, creativity, and approach to problem solving. As such, you may not use AI to complete assigned tasks as part of any assessments. If you plan to use AI-supported or assistive technologies as part of a reasonable adjustment, please contact accommodations@arm.com so we can support you.

Recruitment Adjustments and Accommodations

At Arm, we want to build extraordinary teams. If you need an adjustment or an accommodation during the recruitment process, please email accommodations@arm.com. To note, by sending us the requested information, you consent to its use by Arm to arrange for appropriate accommodations. All accommodation or adjustment requests will be treated with confidentiality, and information concerning these requests will only be disclosed as necessary to provide the accommodation. Although this is not an exhaustive list, examples of support include breaks between interviews, having documents read aloud, or office accessibility. Please email us about anything we can do to accommodate you during the recruitment process.

Hybrid Working

Arm’s approach to hybrid working is designed to create a working environment that supports both high performance and personal wellbeing. We believe in bringing people together face to face to enable us to work at pace, whilst recognizing the value of flexibility. Within that framework, we empower groups/teams to determine their own hybrid working patterns, depending on the work and the team’s needs. Details of what this means for each role will be shared upon application. In some cases, the flexibility we can offer is limited by local legal, regulatory, tax, or other considerations, and where this is the case, we will collaborate with you to find the best solution. Please talk to us to find out more about what this could look like for you.

Equal Opportunities

Arm is an equal opportunity employer, committed to providing an environment of mutual respect where equal opportunities are available to all applicants and colleagues. We are a diverse organization of dedicated and innovative individuals, and don’t discriminate on the basis of race, color, religion, sex, sexual orientation, gender identity, national origin, disability, or status as a protected veteran.