TimeoutManager: delete cuda events on main thread #142
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torchft/futures.py
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| while True: | ||
| try: | ||
| # get and immediately discard item | ||
| self._del_queue.get_nowait() |
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Do we want to do a sanity check to ensure there are no other reference to the event?
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Good suggestion! I added a getrefcount assertion
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This updates the TimeoutManager to use a deletion queue so we delete the CUDA events on the main thread. If we delete these on the background thread we can end up deadlocking and not calling future timeout.
This is critical for NCCL abort as cudaEventDestroy can block in scenarios when a NCCL operation is stuck.
Test plan:
Tested in torchtitan