Stale Rollouts, Fresh Trouble: The Two Speed Limits of Asynchronous RLHF
TL;DR for operators Asynchronous RLHF buys throughput by allowing rollout workers to continue generating completions while the learner updates the policy. The invoice arrives later: some rollouts were generated by a policy that the learner has already left behind. The paper’s useful contribution is not merely the familiar observation that stale data can destabilize training. It identifies two different speed limits.1 ...