[torch.compile] A simple solution to recursively compile loaded model: using phi3-small as an example

[wschin]

It's often hard to apply torch.compile directly to a model because many limitations. However, there are only a few key nn.Modules we really need to compile to get max speed. This PR presents a short solution to solve the problem. Phi3-small got 15% latency improvement with this.

This PR contains 3 major functions:

• register_module_to_compile: it registers which torch.nn.Module to compile when scanning child modules from top to bottom (e.g., from Phi3 to MLP, layernorm).
• compile_child_modules: it is called after model is loaded to visit child nn.Module's from top (e.g., GPT2) to bottom (e.g., MLP). If a nn.Module is compiled, its child nn.Module's won't be compiled again.
• unregister_module_to_compile: it undoes register_module_to_compile.
• To enable this feature set COMPILE_CHILD_NN_MODULES=1.

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[wschin]

@youkaichao, did you get a chance to review? @comaniac, it'd nice if you can help reviewing. At least, let me know if I should continue writing test. This solution is extremely simple and effective.

Thank you.

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had any activity within 90 days. It will be automatically closed if no further activity occurs within 30 days. Leave a comment if you feel this pull request should remain open. Thank you!

[mergify[bot]]

This pull request has merge conflicts that must be resolved before it can be merged. Please rebase the PR, @wschin.

https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/working-with-forks/syncing-a-fork

[github-actions[bot]]

This pull request has been automatically marked as stale because it has not had any activity within 90 days. It will be automatically closed if no further activity occurs within 30 days. Leave a comment if you feel this pull request should remain open. Thank you!

[github-actions[bot]]

This pull request has been automatically closed due to inactivity. Please feel free to reopen if you intend to continue working on it. Thank you!