titleCluster, Route, Escalate: Cascaded Framework for Cost-Aware LLM Serving
authorsYasmin Moslem, Magdalena Kacmajor, Vasudevan Nedumpozhimana, Ammar Abbas, Solmaz Panahi, David Lynch, Zhuangzhuang Nie, Alexandros Agapitos, Aleksandar Milenovic, Hongmeng Song, Yucheng Shi, Yue Pan, Patricia Buffini, John D. Kelleher
date2026-06-25
venuearXiv (preprint, not peer reviewed)
idarXiv:2606.27457
upvotes4 (Hugging Face Daily Papers, 2026-11-01)
linksabs pdf hf code
abstractEfficient deployment of large language models (LLMs) in production forces a trade-off between accuracy and cost. Operators often default to a single model that is either expensive for easy queries or insufficient for hard ones. To address this challenge, we propose a two-stage cascaded solution. Stage 1 clusters incoming queries and assigns each cluster to its most cost-effective model. The cost budget for this routing process is set by an interpretable hyperparameter, tuned offline. Stage 2 adds a quality estimation (QE) cascade; when an output from Stage 1 is judged low-quality, the query is escalated to a stronger model. This ensures only hard or low-confidence cases reach the expensive models. On the test datasets, the cascaded system retains 97-99% of the strongest model's accuracy while reducing Time Per Output Token (TPOT). It requires only task-correctness labels and adapts to changes in the model pool without manual reconfiguration.

cite

@misc{moslem2026cluster,
  title={Cluster, Route, Escalate: Cascaded Framework for Cost-Aware LLM Serving},
  author={Yasmin Moslem and Magdalena Kacmajor and Vasudevan Nedumpozhimana and Ammar Abbas and Solmaz Panahi and David Lynch and Zhuangzhuang Nie and Alexandros Agapitos and Aleksandar Milenovic and Hongmeng Song and Yucheng Shi and Yue Pan and Patricia Buffini and John D. Kelleher},
  year={2026},
  eprint={2606.27457},
  archivePrefix={arXiv},
  url={https://arxiv.org/abs/2606.27457}
}