ResearchResearch paperReinforcement Learning1 source · Oct 7, 2026

CERO: Where and When to Allocate Rollouts for RL Post-Training

Adaptive rollout methods for group-relative reinforcement learning typically allocate a fixed per-update budget across prompts.

Key points

  • We instead study how to coordinate a finite rollout budget over the entire training horizon.
  • We formulate this problem using a concave surrogate utility of cumulative prompt exposure and introduce CERO, an online primal dual scheduler for prompt admission and budget pacing.
  • A compact Fenchel representation linearizes the dependence on cumulative exposure, while projected online gradient descent updates prompt-specific supporting slopes and a shared budget price using reward-variation feedback and budget deviations.
  • We establish pathwise guarantees for the surrogate allocation objective against fixed-rate and same-path time-varying benchmarks, with explicit terms for proxy discrepancy and rate variation.

Sources (1)

  • [1]CERO: Where and When to Allocate Rollouts for RL Post-Training
    arXiv (AI, ML, NLP, CV, robotics, multi-agent) · Oct 7, 08:40 AM
    Adaptive rollout methods for group-relative reinforcement learning typically allocate a fixed per-update budget across prompts.
    We instead study how to coordinate a finite rollout budget over the entire training horizon.

Extractive summary: sentences quoted from the sources.

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