Principal Kernel Engineer

European Tech Recruit; Cambridgeshire and Peterborough; On-site; GBP 120,000 - 180,000; Full time

Job summary

European Tech Recruit partners with a leading telecommunications R&D company in Cambridge to hire a Principal Kernel Engineer. The role focuses on deep kernel performance and power optimization across mobile platforms, owning core subsystems, and delivering production-grade patches.

You will work with CPU microarchitects, runtime engineers, and AI-driven optimization tools to push the boundaries of kernel efficiency and responsiveness on flagship workloads, including gaming and AI inference.

Qualifications

• 10+ years of OS kernel development in C (Linux or comparable).
• Expert-level understanding of MM internals: memory management, ordering, TLBs.
• Mastery of kernel synchronization: RCU, locking, ARM64 barriers.
• Proven kernel performance-analysis skills: PMU counters, ftrace/perf, eBPF.
• Strong ARM64 architecture grounding: cache, memory ordering, TLBs.
• Mobile/SoC power engineering: DVFS, cpuidle, energy attribution.
• Upstream Linux kernel contributions (MM, sched, locking).

Responsibilities

• Optimize memory management internals: buddy allocator, slab/SLUB, page reclaim, and memory defragmentation.
• Drive scheduler performance: run-queue, load balancing, energy-aware scheduling.
• Optimize synchronization primitives and lock-heavy paths: futex paths, mutexes, RCU, atomics.
• Analyse IPC and syscall paths: context-switch cost, shared memory, vDSO, interrupts.
• Identify bottlenecks on flagship mobile workloads: gaming, AI inference, camera using PMU counters and profiling.
• Land production-quality kernel patches from hypothesis through benchmarking.
• Collaborate with CPU microarchitects on HW-SW co-design and kernel-driven requirements.
• Contribute to AI-assisted kernel optimization pipelines.

Skills

Kernel development

C programming

Linux kernel

Performance analysis

ARM64

Power optimization

PMU counters

ftrace/perf

eBPF

Upstream contributions

Job description

European Tech Recruit are working closely with a leading telecommunications R&D company, based in Cambridge, who are looking for a talented Principal Kernel Engineer to join their team.

In this role you will drive deep kernel performance and power optimization for flagship mobile platforms. You will own performance across core kernel subsystems — memory management, scheduling, IPC, and synchronization — analysing behaviour on real silicon down to the microarchitectural level and landing production-shippable optimizations that improve responsiveness, throughput, and battery life.

This is a hands-on role for an engineer who is at home in allocator internals, scheduler hot paths, and lock-contention traces, working alongside CPU microarchitects, runtime engineers, and AI-driven optimization tooling.

Responsibilities as Principal Kernel Engineer:

• Optimize memory management internals: buddy allocator, slab/SLUB, page reclaim and LRU/MGLRU, memory compaction and defragmentation, transparent huge pages, page-fault and TLB-shootdown paths, copy-on-write behaviour.
• Drive scheduler performance: run-queue and load-balancing behaviour, energy-aware scheduling, wakeup latency, task placement on heterogeneous (big.LITTLE/DynamIQ) topologies, cpufreq/cpuidle governor interaction.
• Optimize synchronization primitives and lock-heavy paths: futex fast/slow paths, mutexes and rwsems, spinlocks/qspinlocks, RCU, seqlocks, per-CPU data, memory ordering and barriers on ARM64.
• Analyse and improve IPC and syscall paths: context-switch cost, binder-style IPC, shared memory, vDSO, interrupt/softirq handling.
• Identify bottlenecks on flagship mobile workloads: (gaming, day-of-use, camera, AI inference) using PMU counters, ftrace/perf, eBPF, lockdep/lockstat, and power measurement with mA/mAh attribution.
• Land production-quality kernel patches from hypothesis through benchmarking to ship, with measured latency and energy impact.
• Collaborate with CPU microarchitects on HW-SW co-design: exploit microarchitectural features in the kernel and shape future hardware through kernel-driven requirements.
• Contribute to AI-assisted kernel optimization pipelines.

Requirements:

• 10+ years of OS kernel development in C (Linux or comparable), with patches shipped to production systems at scale.
• Expert-level understanding of MM internals: physical/virtual memory management, buddy and slab allocation, reclaim, compaction, page tables, TLB management.
• Mastery of kernel synchronization: locking primitives, RCU, lock-free techniques, the ARM64 memory model and barrier semantics.
• Proven kernel performance-analysis skills: PMU counters, ftrace/perf, eBPF, lock contention and latency analysis.
• Strong ARM64 architecture grounding: exception levels, cache hierarchy and maintenance, TLBs, memory ordering.
• Mobile power engineering: DVFS governors, cpuidle, per-workload energy attribution.
• Upstream Linux kernel contributions (mm, sched, locking, or related subsystems).
• Familiarity with HarmonyOS or Android common kernel.
• Exposure to CPU microarchitecture and cycle-accurate modelling (gem5).
• Experience with LLM/agentic tooling applied to systems software.

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