Bort is an optimal subset of architectural parameters for the BERT architecture, extracted by applying a fully polynomial-time approximation scheme (FPTAS) for neural architecture search. Bort has an effective (that is, not counting the embedding layer) size of 5.5% the original BERT-large architecture, and 16% of the net size. It is also able to be pretrained in 288 GPU hours, which is 1.2% of the time required to pretrain the highest-performing BERT parametric architectural variant, RoBERTa-large. It is also 7.9x faster than BERT-base (20x faster than BERT/RoBERTa-large) on a CPU, and performs better than other compressed variants of the architecture, and some of the non-compressed variants; it obtains an average performance improvement of between 0.3% and 31%, relative, with respect to BERT-large on multiple public natural language understanding (NLU) benchmarks.
Bort
2020
Last updated October 9, 2023