Robust Batch-Level Query Routing for Large Language Models under Cost and Capacity Constraints

Fuente: arXiv
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Main Authors: Markovic-Voronov, Jelena, Behdin, Kayhan, Xu, Yuanda, Zhou, Zhengze, Wang, Zhipeng, Mazumder, Rahul
Format: Preprint
Published: 2026
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author Markovic-Voronov, Jelena
Behdin, Kayhan
Xu, Yuanda
Zhou, Zhengze
Wang, Zhipeng
Mazumder, Rahul
author_facet Markovic-Voronov, Jelena
Behdin, Kayhan
Xu, Yuanda
Zhou, Zhengze
Wang, Zhipeng
Mazumder, Rahul
contents We study the problem of routing queries to large language models (LLMs) under cost, GPU resources, and concurrency constraints. Prior per-query routing methods often fail to control batch-level cost, especially under non-uniform or adversarial batching. To address this, we propose a batch-level, resource-aware routing framework that jointly optimizes model assignment for each batch while respecting cost and model capacity limits. We further introduce a robust variant that accounts for uncertainty in predicted LLM performance, along with an offline instance allocation procedure that balances quality and throughput across multiple models. Experiments on two multi-task LLM benchmarks show that robustness improves accuracy by 1-14% over non-robust counterparts (depending on the performance estimator), batch-level routing outperforms per-query methods by up to 24% under adversarial batching, and optimized instance allocation yields additional gains of up to 3% compared to a non-optimized allocation, all while strictly controlling cost and GPU resource constraints.
format Preprint
id arxiv_https___arxiv_org_abs_2603_26796
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Robust Batch-Level Query Routing for Large Language Models under Cost and Capacity Constraints
Markovic-Voronov, Jelena
Behdin, Kayhan
Xu, Yuanda
Zhou, Zhengze
Wang, Zhipeng
Mazumder, Rahul
Machine Learning
Artificial Intelligence
We study the problem of routing queries to large language models (LLMs) under cost, GPU resources, and concurrency constraints. Prior per-query routing methods often fail to control batch-level cost, especially under non-uniform or adversarial batching. To address this, we propose a batch-level, resource-aware routing framework that jointly optimizes model assignment for each batch while respecting cost and model capacity limits. We further introduce a robust variant that accounts for uncertainty in predicted LLM performance, along with an offline instance allocation procedure that balances quality and throughput across multiple models. Experiments on two multi-task LLM benchmarks show that robustness improves accuracy by 1-14% over non-robust counterparts (depending on the performance estimator), batch-level routing outperforms per-query methods by up to 24% under adversarial batching, and optimized instance allocation yields additional gains of up to 3% compared to a non-optimized allocation, all while strictly controlling cost and GPU resource constraints.
title Robust Batch-Level Query Routing for Large Language Models under Cost and Capacity Constraints
topic Machine Learning
Artificial Intelligence
url https://arxiv.org/abs/2603.26796