Senior Low Latency Kernel Engineer (C++/Linux)

Selby Jennings; Greater London; On-site; GBP 140,000 - 180,000; Full time

Job summary

Selby Jennings is seeking a Senior Low Latency Kernel Engineer to push the limits of Linux, networking, and hardware performance for a top-tier quantitative trading firm in London. The role focuses on kernel tuning, CPU and memory optimization, and ultra-low-latency C++ development.

You'll work with FPGA, infrastructure, and hardware teams to remove bottlenecks across the stack, using perf, eBPF, and ftrace to drive deterministic performance in trading environments.

Qualifications

• 6+ years of modern C++ experience (C++20+).
• Deep expertise in Linux internals, kernel tuning, networking, and systems programming.
• Strong understanding of CPU architecture, cache hierarchies, memory management, and performance profiling.
• Academic excellence from a top university in a quantitative field.

Responsibilities

• Optimising Linux kernels and network stacks for deterministic low-latency performance.
• Analysing CPU, cache, memory, NUMA, and scheduling behaviour.
• Developing high-performance C++20 systems used in trading and market data environments.
• Leveraging perf, eBPF, and ftrace to identify and remove bottlenecks.

Skills

C++20

Linux internals

Kernel tuning

Performance profiling

System programming

HFT exposure

Tools

perf

eBPF

ftrace

Job description

Senior Low Latency Kernel Engineer (C++/Linux)

Want to work where nanoseconds matter?

We're partnering with a top-tier quantitative trading firm seeking a Low-Latency Kernel Engineer to push the limits of Linux, networking, and hardware performance.

This is a deeply technical role focused on kernel tuning, CPU and memory optimization, network stack performance, and ultra-low-latency C++ development. You'll work directly with FPGA, infrastructure, and hardware teams to eliminate bottlenecks across the entire stack.

What you'll be doing:

• Optimising Linux kernels and network stacks for deterministic low-latency performance
• Analysing CPU, cache, memory, NUMA, and scheduling behaviour
• Developing high-performance C++20 systems used in trading and market data environments
• Leveraging tools such as perf, eBPF, and ftrace to identify and remove bottlenecks
• Collaborating with FPGA engineers on hardware-accelerated solutions

What we're looking for:

• 6+ years of modern C++ (C++20+) experience
• Deep expertise in Linux internals, kernel tuning, networking, and systems programming
• Strong understanding of CPU architecture, cache hierarchies, memory management, and performance profiling
• Exceptional academics from a top university in Computer Science, Mathematics, Engineering, Physics, or a related quantitative field
• A genuine passion for low-level performance engineering

Nice to have:

• DPDK, XDP, AF_XDP, RDMA, OpenOnload, or other kernel-bypass technologies
• FPGA or hardware acceleration exposure
• Experience in HFT, trading systems, market data, telecoms, or other latency-sensitive environments

Join a team of elite engineers solving some of the hardest performance challenges in the industry, where every optimisation can directly impact production trading performance.