Processing Large Dataset for Training GPT2 model

I am working with a very big datasource (230M documents) and am trying to train a GPT2 style model using script with Deepspeed. There is a grouping function in the script (transformers/ at main 路 huggingface/transformers 路 GitHub) which breaks the data into multiple tokens of max_sequence length.

Since my data is so big, the total time showing for me is around 10 days., which is way too much for pre-processing a data. Is there a way I can fasten up the process?

Hi ! Have you tried increasing preprocessing_num_workers ?

Yeah, I have the maximum number of processors that my system has. Is there a way to replace this function with something which is faster?

This function uses pythons lists, which are known to be slow. Using NumPy is significantly faster since it鈥檚 integrated with Apache Arrow - the format used to store the datasets.

Therefore you should manipulate NumPy arrays instead. To do that, use the 鈥渘umpy鈥 formatting:

tokenized_datasets = tokenized_datasets.with_format("numpy")
lm_datasets =

And you can modify your map function to work with NumPy arrays only, instead of lists.

(it can even be slightly faster using the 鈥渁rrow鈥 formatting, but it would require to rewrite your map function completely so I wouldn鈥檛 suggest it)

I was also noticing this 鈥渋ssue鈥 as well when trying to map the Pile. The estimated time would have been ~10 days to tokenize on 48 proc. I will try with numpy.