[trainer] renaming cl args/ trainer attributes to be clear per-gpu vs total
As we started discussing here https://github.com/huggingface/transformers/issues/9801#issuecomment-767825869 perhaps we could have a design session where we look at all of the trainer cl args (and their class attribute counterparts) and see which of them contain ambiguity wrt per-gpu vs total (and perhaps other important renames where we find things are confusing).

The intention is to make the API more intuitive and minimize the number of time we introduce breaking changes, but to attempt to do that in one go as much as possible.

One such item we started to discuss is `--max_steps`, then @sgugger mentioned `--num_train_epochs` and there are probably others.

I also proposed to potentially entertain creating a back-compat module to minimize the breaking changes pain where it's possible - renames fall perfectly into this category. I wrote:

> In some previous projects for such things we also had a back-compat mode, which ones enabled supported a whole bunch of old ways until the user was ready to make the shift to the new code. Surely a rename of a cl arg could be easily supported by such feature. So here, instead of a deprecation cycle per item the approach is to keep anything old around but only if it's loaded from a helper module. So that the main code remains clean of deprecated things. This was in a different programming environment where it was developer, so I will have to think how to do the same here.


@LysandreJik, @patrickvonplaten, @sgugger 

This issue has been automatically marked as stale and been closed because it has not had recent activity. Thank you for your contributions.

If you think this still needs to be addressed please comment on this thread.<|||||>I'd love to get feedback on that. Thank you!<|||||>As it doesn't seem to resonate as a real need, I'm closing this one.