Xunnan Xu is a software engineer with 10 years of experience building large-scale distributed systems and ML infrastructure, now a Member of Technical Staff at a stealth AI startup in San Francisco. Previously at Meta he focused on distributed training resilience, communication optimization (ncclx zero SM comm overlapping), and elastic checkpointing at production scale. He contributes to PyTorch’s core, improving memory and shared-memory support for distributed workloads, reflecting deep low-level systems and ML-runtime expertise. Xunnan combines academic rigor from an MS in Computer Science (USC) with practical experience in cluster scheduling and ad-tech, and favors quiet, high-impact engineering over showy work.
10 years of coding experience
8 years of employment as a software developer
Master of Science (MS) Computer Science, Master of Science (MS) Computer Science at University of Southern California
Bachelor of Science - BS Industrial Engineering, Bachelor of Science - BS Industrial Engineering at Shanghai Jiao Tong University
Tensors and Dynamic neural networks in Python with strong GPU acceleration
Role in this project:
Back-end Developer
Contributions:40 reviews, 21 PRs, 13 pushes in 3 years 3 months
Contributions summary:Xunnan primarily contributes to the PyTorch library's core functionalities by implementing and modifying low-level storage and memory management features. Their work includes adding support for shared memory within the ATen library, enabling memory sharing across processes, and integrating new functionalities like the `share_memory_()` method to `TensorBase`. Additionally, the user addresses critical issues by backing out problematic changes and correcting errors in existing code, such as those related to the handling of sharding and placement within the distributed training framework. These contributions focus on enhancing the library's capabilities in distributed training and memory efficiency.
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