Does DataLoader prefetch_factor matters when num_workers=0?

Default prefetch_factor=2 and num_workers=0, but documentation says that “there will be a total of prefetch_factor * num_workers samples prefetched”. As num_workers=0 means main thread does fetching of batch, so will prefetch_factor will work in this case?

I don’t think the main thread is able to prefetch the data, so the argument shouldn’t change the behavior.
The default value is most likely set, since usually the num_workers argument is changed while the prefetch_factor is often not touched.