Senior Software Engineer – AI Middleware

Cornelis Networks develops high-performance networking solutions for AI and HPC datacenters. The Senior Software Engineer will design, develop, and upstream-enable AI communication middleware, optimizing collective communications and distributed AI workloads over Cornelis Networks interconnects.

Responsibilities

• Design and implement performance-critical features for CCL enablement on Cornelis Networks’ fabrics
• Optimize distributed training performance across multi-node, multi-GPU configurations
• Improve GPU communication paths including GPU-direct transfers, IPC, and CPU/GPU synchronization
• Profile distributed AI workloads and identify bottlenecks across the software and hardware stack
• Tune AI frameworks such as PyTorch Distributed, TensorFlow/XLA, JAX, DeepSpeed, and Megatron-LM
• Develop benchmarks and microbenchmarks aligned with real model performance
• Contribute upstream to AI communication and distributed training projects
• Participate in design reviews, code reviews, CI, and long-term maintenance
• Prototype and validate Ultra Ethernet capabilities for AI collective communication
• Provide technical input for deployment considerations and performance validation
• Collaborate with kernel/driver, switch, performance, and systems teams
• Support advanced escalations by analyzing traces and providing robust fixes

Preferred

• Experience with AI frameworks such as PyTorch Distributed, DeepSpeed, and Megatron-LM
• Familiarity with libfabric/OFI, UCX, and RDMA concepts
• Experience with RoCEv2 and Ultra Ethernet
• Experience building cluster-scale performance test infrastructure
• PyTorch Distributed
• DeepSpeed
• Megatron-LM
• libfabric/OFI
• UCX
• RDMA
• RoCEv2
• Ultra Ethernet
• Cluster-Scale Performance Testing
• Test Infrastructure Development

Benefits

• Equity
• Performance-based incentives, including an annual bonus or sales incentives, depending on role
• Remote position for employees residing within the United States
• Flexible work environment
• Medical, dental, and vision coverage
• Disability and life insurance
• Dependent care flexible spending account
• Accidental injury insurance
• Pet insurance
• Generous paid holidays
• 401(k) with company match
• Open Time Off (OTO) for regular full-time exempt employees
• Sick time
• Bonding leave
• Pregnancy disability leave

Company

• Zero-congestion networking for AI and HPC
• Wayne, Pennsylvania, USA
• https://www.cornelis.com/
• Founded in 2020
• 201-500 employees

Qualifications

• 8+ years of experience in high-performance systems programming in C/C++ on Linux
• Strong experience with GPU communication stacks including CUDA/ROCm and NCCL/RCCL
• Ability to optimize distributed training performance using profiling and tracing
• Understanding of collective communication concepts and topology awareness
• Experience delivering production-quality code
• Open-source contributions in relevant areas
• Experience with AI frameworks such as PyTorch Distributed, DeepSpeed, and Megatron-LM
• Familiarity with libfabric/OFI, UCX, and RDMA concepts
• Experience with RoCEv2 and Ultra Ethernet
• Experience building cluster-scale performance test infrastructure
• 8+ years of experience in high-performance systems programming in C/C++ on Linux.

Required skills

• C/C++, CUDA, DeepSpeed, Distributed Training, Libfabric/OFI, Linux Systems Programming, Megatron-LM, NCCL, Performance Profiling and Tracing, PyTorch Distributed, RCCL, RDMA, ROCm, RoCEv2, UCX, Ultra Ethernet

Preferred skills

• Experience with RoCEv2 and Ultra Ethernet, Familiarity with libfabric/OFI, UCX, and RDMA concepts

Experience

• 8+ years