Ethernet Performance Engineer

Cornelis Networks delivers the world’s highest performance scale-out networking solutions for AI and HPC datacenters. Our differentiated architecture seamlessly integrates hardware, software and system level technologies to maximize the efficiency of GPU, CPU and accelerator-based compute clusters at any scale. Our solutions drive breakthroughs in AI & HPC workloads, empowering our customers to push the boundaries of innovation. Backed by top-tier venture capital and strategic investors, we are committed to innovation, performance and scalability - solving the world’s most demanding computational challenges with our next-generation networking solutions.

We are a fast-growing, forward-thinking team of architects, engineers, and business professionals with a proven track record of building successful products and companies. As a global organization, our team spans multiple U.S. states and six countries, and we continue to expand with exceptional talent in onsite, hybrid, and fully remote roles.

We’re seeking a Senior Ethernet Performance Engineer to lead performance validation, debug, and characterization of our next-generation Ethernet-based networking silicon products-both internally and in customer environments. You’ll play a key role in post-silicon bring-up, lab-based performance validation, and collaboration with customers to optimize system performance. This is a high-impact, cross-functional role with visibility across silicon design, system architecture, software, and customer engineering teams.

Key Responsibilities:

• Building, configuring, and benchmarking Ethernet fabrics with RoCEv2 (RDMA over Converged Ethernet) to perform head-to-head performance evaluations against other network architectures (InfiniBand, Omni-Path, and rival Ethernet solutions).

• Develop and execute validation and performance test plans targeting both internal lab and real-world data center deployment scenarios.

• Analyze performance metrics such as throughput, latency, congestion, power efficiency, and architectural behavior under networking workloads.

• Work directly with customers and field teams to reproduce, debug, and optimize performance issues in production environments.

• Create diagnostic tools and scripts to collect, analyze, and visualize performance data.

• Collaborate with architecture, firmware, and software teams to root-cause performance anomalies and recommend hardware or system-level improvements.

• Translate validation and debug findings into actionable feedback for silicon and systems design.

• Provide technical guidance and support to customers integrating and tuning our products in their data center infrastructures.

• 7+ years of experience in post-silicon validation, performance engineering, or silicon debug for networking or high-performance compute products.

• Strong understanding of networking protocols and technologies (e.g., Ethernet, PCIe, switching, congestion control), PFC, ECN, DCQCN.

• Familiarity with data center performance requirements and benchmarks.

• Scripting and automation skills (Python, Shell, etc.).

• Excellent problem-solving and cross-functional communication skills.

• Comfort working directly with customers, field engineers, and technical partners.

Preferred Qualifications:

• Deep understanding of networking and memory data flows, including technologies such as DPDK, RDMA, or similar high-performance I/O frameworks.

• Background in silicon performance modeling, system architecture, or firmware/hardware co-design.

• Exposure to cloud-scale workload analysis and performance tuning

• Experience running HPC (MPI application benchmarks) & AI (NCCL/RCCL benchmarks).

• Telemetry & Debugging: Investigating PFC deadlocks, packet drops, line-rate throughput, and tail latency using kernel tools, packet captures, and fabric telemetry.

Location:

This role fully supports remote work for employees residing within the United States, with the flexibility to travel to our Chesterbrook Corporate Center located in Wayne, PA occasionally for in-person collaboration.

We offer a competitive compensation package that includes equity, cash, and incentives, along with health and retirement benefits. Our dynamic, flexible work environment provides the opportunity to collaborate with some of the most influential names in the semiconductor industry.

At Cornelis Networks your base salary is only one component of your comprehensive total rewards package. Your base pay will be determined by factors such as your skills, qualifications, experience, and location relative to the hiring range for the position. Depending on your role, you may also be eligible for performance-based incentives, including an annual bonus or sales incentives.

In addition to your base pay, you’ll have access to a broad range of benefits, including medical, dental, and vision coverage, as well as disability and life insurance, a dependent care flexible spending account, accidental injury insurance, and pet insurance. We also offer generous paid holidays, 401(k) with company match, and Open Time Off (OTO) for regular full-time exempt employees. Other paid time off benefits include sick time, bonding leave, and pregnancy disability leave.