Enable User-Driven Early Termination and Caching in Autotuning

[hinriksnaer]

Implements #1331

Summary

Adds support for gracefully terminating autotuning early (via CTRL+C) while saving the best configuration found so far. This allows users to stop autotuning when they see diminishing returns without losing progress.

Implementation

• Added _handle_early_termination() method to AutotuneCacheBase that extracts the best benchmarked config
• Wrapped autotuner.autotune() calls in both code paths (skip_cache and normal) with try/except KeyboardInterrupt
• Config is automatically saved to cache before exiting
• Future runs will use the cached config, skipping autotuning entirely

Users who want immediate termination can press CTRL+C twice or use kill -9.

Discussion

Using try like this never feels elegant enough to me. I did consider making this cleaner with a decorator, but I'd rather keep things simple for now and get some feedback before overcomplicating this.

Are we good on CTRL+C invoking this or do we want to consider something else? I am also not sure if we should prompt the user for this or guard this behind a flag.

[oulgen]

So I'm not entirely convinced that we should cache keyboard interrupted configs by default. Maybe we should prompt the user to ask whether they want to save it. Or maybe some checkpoint system similar to what @yf225 was thinking.

If I ctrl-C during autotune, i dont always want to keep that and having to find and delete the cache file might be annoying

[hinriksnaer]

Thanks @oulgen, these are all solid points. I will see what I can do. In the meantime, could you reference whatever @yf225 had in mind?

[oulgen]

Thanks @oulgen, these are all solid points. I will see what I can do. In the meantime, could you reference whatever @yf225 had in mind?

#1348

[hinriksnaer]

Thanks for sharing @oulgen. Given that this is still in active development, I assume the best thing to do is to wait until the changes land and leverage that functionality to support early stopping. What do you think?

[yf225]

Yes I think once the auto-checkpoint feature is in, we can build on top of it to automatically trigger a checkpoint save when user hits Ctrl-C, which will also print instructions on how to resume from the saved checkpoint.