process_group/ManagedProcessGroup: ensure quorum and PG is configured…

… before operations (#83)

torchft/process_group.py

@@ -19,7 +19,6 @@
 import logging
 import queue
 import threading
-from abc import ABC
 from datetime import timedelta
 from typing import TYPE_CHECKING, Dict, List, Optional, Tuple, Type, Union
 
@@ -507,6 +506,10 @@ def __init__(self, manager: "Manager") -> None:
         self._manager = manager
 
     def allreduce(self, tensors: List[torch.Tensor], opts: object) -> Work:
+        # Ensure we have a valid quorum and are configured before trying to do
+        # any work.
+        self._manager.wait_quorum()
+
         if self._manager.errored() is not None:
             return _DummyWork(tensors)
 

torchft/process_group_test.py

@@ -368,6 +368,7 @@ def test_managed_process_group(self) -> None:
 
         self.assertEqual(manager.report_error.call_count, 0)
         self.assertEqual(manager.wrap_future.call_count, 1)
+        self.assertEqual(manager.wait_quorum.call_count, 1)
 
 
 class DeviceMeshTest(TestCase):