What Matters for Model Merging at Scale?

Fuente: arXiv
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Autori principali: Yadav, Prateek, Vu, Tu, Lai, Jonathan, Chronopoulou, Alexandra, Faruqui, Manaal, Bansal, Mohit, Munkhdalai, Tsendsuren
Natura: Preprint
Pubblicazione: 2024
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author Yadav, Prateek
Vu, Tu
Lai, Jonathan
Chronopoulou, Alexandra
Faruqui, Manaal
Bansal, Mohit
Munkhdalai, Tsendsuren
author_facet Yadav, Prateek
Vu, Tu
Lai, Jonathan
Chronopoulou, Alexandra
Faruqui, Manaal
Bansal, Mohit
Munkhdalai, Tsendsuren
contents Model merging aims to combine multiple expert models into a more capable single model, offering benefits such as reduced storage and serving costs, improved generalization, and support for decentralized model development. Despite its promise, previous studies have primarily focused on merging a few small models. This leaves many unanswered questions about the effect of scaling model size and how it interplays with other key factors -- like the base model quality and number of expert models -- , to affect the merged model's performance. This work systematically evaluates the utility of model merging at scale, examining the impact of these different factors. We experiment with merging fully fine-tuned models using 4 popular merging methods -- Averaging, Task~Arithmetic, Dare, and TIES -- across model sizes ranging from 1B-64B parameters and merging up to 8 different expert models. We evaluate the merged models on both held-in tasks, i.e., the expert's training tasks, and zero-shot generalization to unseen held-out tasks. Our experiments provide several new insights about model merging at scale and the interplay between different factors. First, we find that merging is more effective when experts are created from strong base models, i.e., models with good zero-shot performance. Second, larger models facilitate easier merging. Third merging consistently improves generalization capabilities. Notably, when merging 8 large expert models, the merged models often generalize better compared to the multitask trained models. Fourth, we can better merge more expert models when working with larger models. Fifth, different merging methods behave very similarly at larger scales. Overall, our findings shed light on some interesting properties of model merging while also highlighting some limitations. We hope that this study will serve as a reference point on large-scale merging for upcoming research.
format Preprint
id arxiv_https___arxiv_org_abs_2410_03617
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle What Matters for Model Merging at Scale?
Yadav, Prateek
Vu, Tu
Lai, Jonathan
Chronopoulou, Alexandra
Faruqui, Manaal
Bansal, Mohit
Munkhdalai, Tsendsuren
Machine Learning
Artificial Intelligence
Computation and Language
Model merging aims to combine multiple expert models into a more capable single model, offering benefits such as reduced storage and serving costs, improved generalization, and support for decentralized model development. Despite its promise, previous studies have primarily focused on merging a few small models. This leaves many unanswered questions about the effect of scaling model size and how it interplays with other key factors -- like the base model quality and number of expert models -- , to affect the merged model's performance. This work systematically evaluates the utility of model merging at scale, examining the impact of these different factors. We experiment with merging fully fine-tuned models using 4 popular merging methods -- Averaging, Task~Arithmetic, Dare, and TIES -- across model sizes ranging from 1B-64B parameters and merging up to 8 different expert models. We evaluate the merged models on both held-in tasks, i.e., the expert's training tasks, and zero-shot generalization to unseen held-out tasks. Our experiments provide several new insights about model merging at scale and the interplay between different factors. First, we find that merging is more effective when experts are created from strong base models, i.e., models with good zero-shot performance. Second, larger models facilitate easier merging. Third merging consistently improves generalization capabilities. Notably, when merging 8 large expert models, the merged models often generalize better compared to the multitask trained models. Fourth, we can better merge more expert models when working with larger models. Fifth, different merging methods behave very similarly at larger scales. Overall, our findings shed light on some interesting properties of model merging while also highlighting some limitations. We hope that this study will serve as a reference point on large-scale merging for upcoming research.
title What Matters for Model Merging at Scale?
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2410.03617