Senior Staff Systems Engineer - Performance Engineer

The Systems Performance team is part of the Computing Squad consists of two distinct workstreams — Orchestration and System Performance — each with its own approach and challenges on managing and improving the foundational infrastructure where the majority of the Nubank's workloads runs. The Performance team is focused on building deep diagnostic tools and performing high-level analysis to reduce latency, infrastructure costs and increase services efficiency. You will be responsible for leading complex performance investigations, identifying systemic bottlenecks, and driving efficiency across one of the largest JVM-based microservice architectures in the world.

Responsibilities

Leading Deep-Dive Investigations: Conduct high-level performance analysis to identify and resolve systemic bottlenecks; Optimizing Resource Efficiency: Drive initiatives to reduce infrastructure costs and latency by fine-tuning JVM parameters, Garbage Collection (ZGC, G1), and memory management; Building Diagnostic Tooling: Develop and implement advanced observability tools using eBPF, JFR, and Flamegraphs; Kernel & Runtime Alignment: Bridge the gap between the Linux Kernel and the JVM, optimizing thread scheduling (CFS/EEVDF) and managing resource isolation (cgroups/throttling) within Kubernetes; Architecting Scalable Solutions: Design and deliver innovative infrastructure improvements; Technical Mentorship & Culture: Share expertise on JVM internals and performance best practices; Root Cause Excellence: Deep dive into complex concurrency issues, lock contentions, and memory leaks; Strategic Collaboration: Work closely with the Computing Squad to align orchestration strategies with system performance goals

Requirements

Expertise in JVM Internals: Deep, low-level knowledge of the JVM; JVM Tuning & Garbage Collection: Extensive experience with GC algorithms (ZGC, G1, Shenandoah); Linux Kernel & Scheduling: Deep understanding of the Linux Scheduler (CFS/EEVDF); Memory Architecture: Mastery of heap and off-heap memory management; Advanced Diagnostics: Mastery of diagnostic tools such as Flamegraphs, JFR, eBPF, and large-scale heap dump analysis; Resource Isolation: Extensive experience with cgroups and CPU Throttling within Kubernetes/EKS; Concurrency: Proven ability to diagnose and resolve complex concurrency problems; Cloud Platforms: Knowledge of AWS infrastructure; Develops and delivers innovative solutions that address team-level or project-level challenges; Understand the technical aspects, capabilities, and limitations of our systems; Anticipate technical and product issues, making appropriate design decisions to avoid them; Is enthusiastic about sharing knowledge and mentoring others; Deep dive into a problem to identify root causes when prioritized

Nice to have

OpenJDK Contribution (Major Plus); Previous experience contributing to the OpenJDK project or other low-level runtime environments