How to Distill your BERT: An Empirical Study on the Impact of Weight Initialisation and Distillation Objectives

Wang, Xinpeng; Weissweiler, Leonie; Schütze, Hinrich und Plank, Barbara (2023): How to Distill your BERT: An Empirical Study on the Impact of Weight Initialisation and Distillation Objectives. The 61st Annual Meeting of the Association for Computational Linguistics, Toronto, Canada, July 9-14, 2023. Rogers, Anna (ed.) : In: Proceedings of the 61st Annual Meeting of the Association for Computational Linguistics, Vol. 2 Stroudsburg, PA: Association for Computational Linguistics. pp. 1843-1852

Abstract

Recently, various intermediate layer distillation (ILD) objectives have been shown to improve compression of BERT models via Knowledge Distillation (KD). However, a comprehensive evaluation of the objectives in both task-specific and task-agnostic settings is lacking. To the best of our knowledge, this is the first work comprehensively evaluating distillation objectives in both settings. We show that attention transfer gives the best performance overall. We also study the impact of layer choice when initializing the student from the teacher layers, finding a significant impact on the performance in task-specific distillation. For vanilla KD and hidden states transfer, initialisation with lower layers of the teacher gives a considerable improvement over higher layers, especially on the task of QNLI (up to an absolute percentage change of 17.8 in accuracy). Attention transfer behaves consistently under different initialisation settings. We release our code as an efficient transformer-based model distillation framework for further studies.

• Item Type: Conference or Workshop Item (Paper)
• Faculties: Languages and Literatures > Department 2
• Research Centers: Center for Information and Language Processing (CIS)
• Subjects: 000 Computer science, information and general works > 004 Data processing computer science; 400 Language > 410 Linguistics
• ISBN: 978-1-959429-71-5
• Place of Publication: Stroudsburg, PA
• Language: English