Explain what torch.distributed.barrier does
Company: OpenAI
Role: Machine Learning Engineer
Category: Software Engineering Fundamentals
Difficulty: hard
Interview Round: Onsite
## Question
In PyTorch distributed training, what does `torch.distributed.barrier()` do?
## Follow-ups
- Give an example of when you would use it.
- What are the risks of calling it incorrectly?
- How does it relate to deadlocks and performance?
Quick Answer: This question evaluates understanding of PyTorch distributed synchronization primitives, process coordination, and concurrency control in distributed training workflows.