Low Latency Linux Engineer

iSAM is an innovative, financial technology firm specialising in quantitative trading, compromised of iSAM Funds and iSAM Securities.

iSAM Securities regulated by the FCA, SFC, and CTFC, and CIMA registered, is a leading algorithmic trading firm and trusted electronic market maker, providing liquidity, technology and prime services to institutional clients and trading venues globally. The firm offers full-service prime brokerage and execution via its cutting-edge proprietary technology, as well as market leading analytics, cleared through the group’s bank Prime Brokers.

iSAM Funds is an alternative asset manager specialising in systematic investing. Each strategy is unique, provides a specialist quantitative approach and is designed to deliver highly diversifying absolute returns for institutional portfolios.

About the Role:

We are seeking an exceptional Low Latency Linux Engineer to optimize our global low-latency trading infrastructure. This is a high-impact role where your engineering choices will have a direct and measurable effect on trading performance, execution quality, and overall profitability.

You will combine hands-on technical depth with a strategic approach to system, network, and market data performance tuning. Working alongside world-class developers, quants, and platform engineers, you’ll design, deploy, and refine deterministic, microsecond-level systems that underpin our trading platforms.

This is far from a traditional sysadmin position — it’s a role for exceptional engineers immersed in the Linux ecosystem, who thrive on tackling kernel-level challenges, pushing bare-metal systems to their limits, and writing performance-critical code. You’ll engineer and refine the RHEL platform that drives ultra-low-latency trading, addressing intricate problems in CPU scheduling, memory architecture, kernel bypass techniques, and performance-aware virtualization. Some investigations may take weeks or months to solve — this role demands persistence, precision, and a genuine passion for performance engineering.

Key Responsibilities

• OS Engineering & Tuning: Customize and refine RHEL for high-performance, low-latency workloads, including kernel parameters, IRQ handling, CPU pinning, NUMA optimization and memory management.
• Kernel Bypass & User-Space Networking: Implement and optimize technologies such as Solarflare OpenOnload/TCPDirect/ef_vi, DPDK, InfiniBand verbs, or Exablaze to minimize network stack latency.
• Bare-Metal Performance: Tune BIOS/firmware; optimize CPU scheduling, cache utilization, and pipeline efficiency for deterministic execution.
• High-Performance Storage: Deploy and fine-tune NVMe over RoCE for ultra-fast data access in trading environments.
• Precision Timing: Manage and optimise PTP across the estate.
• Observability & Diagnostics: Build and enhance monitoring and alerting and implement a packet capture solution for latency analysis.
• Coding & Debugging: Write and maintain high-performance tooling in Java, Python, or Golang to support infrastructure performance, profiling, and automation.
• Cross-Team Collaboration: Partner with quants, network engineers and platform engineers to integrate performance enhancements into trading platforms.

Core Technical Skills & Experience

Required:

• Proven RHEL/Linux performance engineering expertise in ultra-low-latency environments.
• Strong programming skills in Java, Python, or Golang, with ability to debug at system and kernel levels.
• Experience with hardware performance counters, profiling tools, and in-depth performance analysis.
• Deep knowledge of modern CPU architectures (Intel & AMD), including cache hierarchies and NUMA considerations.
• Hands-on experience with kernel-bypass frameworks (Solarflare OpenOnload/TCPDirect/ef_vi, DPDK, InfiniBand verbs, Exablaze).
• Understanding of managed runtime performance challenges (Java, C#) and mitigation strategies.
• Understanding of FIX protocol and multicast messaging concepts.
• Familiarity with PTP timing solutions and packet capture analysis.
• Designing and implementing automation solutions using Infrastructure as Code (IaC) tools such as Ansible, Python, and Terraform to streamline and standardize operational workflows.

Personal Attributes:

• Clear communication – explains technical concepts concisely and effectively
• Adaptability – adjusts to new technologies and unexpected challenges
• Analytical thinking – breaks down complex issues logically and methodically
• Decision-making – balances speed and accuracy when making technical decisions
• Collaboration over competition – prioritises team success over individual wins
• Accountability – follows through on commitments and owns mistakes
• Patience – supports teammates as they learn or troubleshoot issues
• Open to feedback – accepts and applies suggestions for improvement
• Growth mindset – always looks for ways to improve skills and workflows
• Proactiveness – takes initiative instead of waiting for instructions