
Frontier Model Training Infrastructure
The frontier-lab training infrastructure continues to evolve, now supporting post-training of models like GLM 5.2 into specialized agents. This involves advanced asynchronous reinforcement learning techniques, achieving significant improvements in agentic benchmarks with minimal regression on knowledge benchmarks and effectively flat cost per task. The platform's unified training and inference stacks ensure numeric alignment and batch invariance, offering end-to-end zero KLD across training and inference. This post specifically details the critical importance of numerical alignment between training and inference for RL, especially with MoE models, and how Fireworks addresses this through co-optimized trainer/rollout engines, router replay, and validation metrics like training-inference KL.
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