Senior CPU Performance Engineer

CPU Performance Engineer (Device-Level Analysis)OverviewWe are hiring a CPU Performance Engineer focused on device-level performance analysis. This role sits at the intersection of real-world system behaviour and CPU microarchitecture, with the objective of understanding performance observed on devices and translating it into actionable insights for CPU design teams.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.Key ResponsibilitiesDevice Performance AnalysisAnalyse performance on real devices using real-world workloadsSupport investigation of system-level performance issues, identifying CPU-related factorsOperate effectively in low-observability environments (e.g. no waveforms, partial counters, noisy systems)CPU-Focused AnalysisUse PMU counters and profiling tools to understand CPU behaviourContribute to identifying performance bottlenecks (e.g. memory, front-end/back-end, execution)Build understanding of how microarchitectural features impact real-world performancePre-Silicon SupportAssist with experiments on emulation or FPGA platforms to validate hypothesesReproduce silicon-observed behaviours in controlled environments to isolate CPU effectsWhere applicable, compare silicon vs model vs emulation to build confidence in findingsInfluencing CPU ArchitectureContribute analysis and data to support discussions with CPU architecture teamsHighlight gaps between real-world workloads and existing design assumptionsDocument findings and communicate insights clearly to stakeholdersMethodology & ToolingUse and progressively improve performance analysis workflows and toolsContribute to automation and data analysis where relevantRequired Skills & ExperienceStrong 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 countersBasic programming or scripting skills (Python, C/C++, or similar)Strong analytical and problem-solving skillsPreferred ExperienceExposure to CPU performance analysis or benchmarkingFamiliarity with low-level programming (C / Assembly)Basic understanding of RTL or hardware design conceptsExposure to FPGA or emulation platformsExperience working on real devices (mobile, embedded, or client systems)Awareness of system-level performance interactions (OS, scheduling, memory)Familiarity with Arm architectureCandidate ProfileInterested in understanding how real-world workloads interact with CPU architectureComfortable working with noisy, incomplete, or ambiguous dataEager to learn from and collaborate with experienced engineersClear communicator, able to present analysis with appropriate guidanceAdditional Information Please note this role does not meet the eligibility requirements for sponsorship, and therefore the successful candidate must have the right to work in the UK without relying on sponsorship by Arm.Accommodations at ArmAt 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 ArmArm’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 ArmArm 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.