Title: DaMo: Data Mixing Optimizer in Fine-tuning  Multimodal LLMs for Mobile Phone  Agents
Primary area: foundation or frontier models, including LLMs
Keywords: data mixing, multitask, fine-tuning, multimodal, agent

Abstract: Mobile Phone Agents (MPAs) have emerged as a promising research direction due to their broad applicability across diverse scenarios. While Multimodal Large Language Models (MLLMs) serve as the foundation for MPAs, their effectiveness in handling multiple mobile tasks simultaneously remains limited. Although multitask supervised fine-tuning (SFT) is widely adopted for multitask learning, existing approaches struggle to determine optimal training data compositions for peak performance. To address this challenge, we propose DaMo (Data Mixture Optimizer) – a novel solution employing a trainable network that predicts optimal data mixtures by forecasting downstream task performance for any given dataset ratio. To support comprehensive evaluation, we introduce PhoneAgentBench, the first specialized benchmark for mobile-task MLLMs, comprising 1,235 QA pairs spanning diverse real-world industrial mobile application scenarios. Demonstrating strong predictive capability (R²=0.81) in small-scale pilot experiments, DaMo efficiently extrapolates optimal data mixing configurations. Our results show DaMo achieves a 3.38\% performance improvement on PhoneAgentBench compared to alternative methods. Furthermore, extensive experiments across established benchmarks including BFCL-v3, MME-Reasoning, MME-Perception, and OCRBench reveal DaMo’s superior generalization, outperforming other approaches by 2.57\% in terms of average score. When used solely for MLLM optimization on the BFCL-v3 task, DaMo improves the metrics by 12.47\% than other methods. Notably, DaMo maintains robust scalability, preserving its effectiveness when applied to other model architectures.

TL;DR: We propose a Data Mixing Optimizer in fine-tuning  multimodal LLMs for mobile phone  agents and introduce PhoneAgentBench which is a specialized benchmark for mobile-task evaluation.