All Language Models Large and Small
Zhixun Chen, Yali Du, David Mguni
TL;DR
All Language Models Large and Small presents LONDI, a framework that learns when to call a costly DEEPTHINK LM by coupling it with a fast QUICK LM through a switching-control RL agent. The core idea is to formulate activation as a Markov decision process and to optimize a policy that balances task performance against computational cost via a per-activation penalty $c$, with a budgeted variant LONDI-B handling explicit DEEPTHINK call limits. The authors prove convergence to the optimal activation policy and demonstrate substantial resource savings (up to 30% GPU reduction) on ScienceWorld and BabyAI-Text while maintaining strong task performance. They also show that LONDI-B can operate as a plug-and-play framework, adaptable to different LMs and encoders, and provide a budget-aware extension that preserves performance within fixed DEEPTHINK call budgets. The work has practical implications for deploying capable LMs on resource-constrained devices by enabling selective outsourcing of expensive reasoning to larger models only where needed.
Abstract
Many leading language models (LMs) use high-intensity computational resources both during training and execution. This poses the challenge of lowering resource costs for deployment and faster execution of decision-making tasks among others. We introduce a novel plug-and-play LM framework named Language Optimising Network Distribution (LONDI) framework. LONDI learns to selectively employ large LMs only where complex decision-making and reasoning are required while using low-resource LMs (i.e. LMs require less GPU usage, but may not be able to solve the problem alone) everywhere else. LONDI consists of a system of two (off-)policy networks, an LM, a large LM (LLM), and a reinforcement learning module that uses switching controls to quickly learn which system states to call the LLM. We then introduce a variant of LONDI that maintains budget constraints on LLM calls and hence its resource usage. Theoretically, we prove LONDI learns the subset of system states to activate the LLM required to solve the task. We then prove that LONDI converges to optimal solutions while also preserving budgetary constraints on LLM calls almost surely enabling it to solve various tasks while significantly lowering computational costs. We test LONDI's performance in a range of tasks in ScienceWorld and BabyAI-Text and demonstrate that LONDI can solve tasks only solvable by resource-intensive LLMs while reducing GPU usage by up to 30%.
