CheckpointServer: start in disallowed state + tests #90
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| @@ -117,7 +141,9 @@ def do_GET(self): | |||
| # validate socket timeout is actually set | |||
| assert self.connection.gettimeout() == self.timeout | |||
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Would it make sense to add an assert to check self._step == -1 (or maybe initialize step to None and check that) to fail quickly rather than to wait and timeout?
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We actually are doing that which is the issue. Down below we check if self._step == the requested step
We end up with a race condition between send_checkpoint and the remote worker requesting the checkpoint which causes the requester to get an error due to mismatched step
This lock allows us to have some tolerance when requesting a checkpoint. We could busy loop/retry on caller side but the lock makes the code simpler and a bit more efficient
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This fixes a regression that was introduced in #81.
We need to start checkpoint server in disallowed state so new requests coming in will block until the first time we call
send_checkpoint. This prevents requesters erroring out on the first request since the server only has step-1.This also added a timeout on acquiring the lock in the server thread (since we already timeout the socket) so don't want to get stuck there.
Test plan:
Added
disallow_checkpointcall in torchtitanAdded unit tests for this behavior