What problem does it solve?
This Skill helps you implement and troubleshoot large-scale distributed training using PyTorch Fully Sharded Data Parallel (FSDP), addressing common issues like inefficient sharding, mixed-precision pitfalls, CPU offloading configuration, and correctness/performance bottlenecks.
Core Features & Use Cases
- FSDP design guidance (FSDP2-focused): Understand when to use FSDP2 vs FSDP1 concepts like parameter sharding, unshard/reshard hooks, and optimizer expectations.
- Performance & memory configuration: Choose practical settings for mixed precision and CPU offloading to fit models into limited GPU memory while keeping throughput stable.
- Distributed correctness patterns: Apply reliable distributed training patterns (e.g., handling uneven inputs via join context concepts) to avoid hangs and mismatched collectives in real training loops.
Quick Start
Use the pytorch-fsdp skill to design an FSDP2 training setup for your model with mixed precision and CPU offloading, including how to verify correctness and performance.