xFormers is using the root logger

[patricklabatut]

🐛 Bug

I noticed that xFormers logs using the root logger instead of its own library logger (this can be seen in the various logging.{debug,info,...}() calls in the library's code).

This leads to log messages like this:

W20220901 02:40:33 836489 root __init__.py:76] Triton is not available, some optimizations will not be enabled.

These may make it difficult for users to identify their origin (root is the root logger).

It's common practice for libraries to use there own logger for this reason. The fix here would consists in replacing calls to logging.{debug,info,...}() by calls to logger.{debug,info,...}() where logger = logging.getLogger("xformers").

To Reproduce

Steps to reproduce the behavior:

1. set up logging (with a format that includes the logger name),
2. import a basic xformers (w/o any extra features),
3. read the produced log messages.

Expected behavior

Logging messages from xFormers can clearly be identified as coming from this library and the above message looks like:

W20220901 02:40:33 836489 xformers __init__.py:76] Triton is not available, some optimizations will not be enabled.