Senior CPU Performance Engineer

You will work on silicon platforms and real devices, analysing performance across complex and often non-deterministic environments. The role requires a solid foundation in CPU fundamentals, along with a strong interest in understanding how system-level behaviour maps to underlying microarchitecture.

Working alongside experienced architects and performance engineers, you will contribute to investigations, build supporting evidence, and help guide CPU design decisions.

This is not a CPU design or microarchitecture role. Instead, you will influence CPU architecture by identifying bottlenecks, validating hypotheses (where possible) using pre-silicon platforms (e.g. FPGA, emulation, performance models), and driving data-backed recommendations to CPU teams., * Analyse performance on real devices using real-world workloads

• Support investigation of system-level performance issues, identifying CPU-related factors
• Operate effectively in low-observability environments (e.g. no waveforms, partial counters, noisy systems)

CPU-Focused Analysis

• Use PMU counters and profiling tools to understand CPU behaviour
• Contribute to identifying performance bottlenecks (e.g. memory, front-end/back-end, execution)
• Build understanding of how microarchitectural features impact real-world performance

Pre-Silicon Support

• Assist with experiments on emulation or FPGA platforms to validate hypotheses
• Reproduce silicon-observed behaviours in controlled environments to isolate CPU effects
• Where applicable, compare silicon vs model vs emulation to build confidence in findings

Influencing CPU Architecture

• Contribute analysis and data to support discussions with CPU architecture teams
• Highlight gaps between real-world workloads and existing design assumptions
• Document findings and communicate insights clearly to stakeholders

Methodology & Tooling

• Use and progressively improve performance analysis workflows and tools
• Contribute to automation and data analysis where relevant

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

Preferred Experience

• Exposure to CPU performance analysis or benchmarking
• Familiarity with low-level programming (C / Assembly)
• Basic understanding of RTL or hardware design concepts
• Exposure to FPGA or emulation platforms
• Experience working on real devices (mobile, embedded, or client systems)
• Awareness of system-level performance interactions (OS, scheduling, memory)
• Familiarity with Arm architecture, * Interested in understanding how real-world workloads interact with CPU architecture
• Comfortable working with noisy, incomplete, or ambiguous data
• Eager to learn from and collaborate with experienced engineers
• Clear communicator, able to present analysis with appropriate guidance

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 at Arm 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 at Arm 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. Salary Range: £73,500 - £99,500 per year