Auto3d doesn't set OMP_NUM_THREADS

[AHarouni]

Describe the bug
Running Auto3d I get warning of

OMP_NUM_THREADS set to 1 to avoid system overload

we should smartly export this variable before the torchrun

I tired exporting it myself but this doesn't work with multiple nodes. I think this parameter needs to be set in the python code itself

[wyli]

I think it is nice that torchrun automatically modifies the system setting for better performance and creates a warning message to notify the user. what's not working with multi-node?

[myron]

@AHarouni it's one of the pytorch/torchrun info messages. we've all been seeing it a lot even in other codes. I don't think we should set it (to keep it auto), but perhaps we can hide that warning somehow (or just leave it be)