Skip hanging spawn tests

pytorch_lightning/plugins/training_type/ddp_spawn.py

@@ -25,7 +25,6 @@
 from torch.nn.parallel.distributed import DistributedDataParallel
 
 import pytorch_lightning as pl
-from pytorch_lightning.loggers import LoggerCollection, TensorBoardLogger
 from pytorch_lightning.overrides import LightningDistributedModule
 from pytorch_lightning.overrides.distributed import prepare_for_backward
 from pytorch_lightning.plugins.environments.cluster_environment import ClusterEnvironment
@@ -149,17 +148,14 @@ def get_mp_spawn_kwargs(self, trainer: Optional["pl.Trainer"] = None) -> Dict[st
         return {"nprocs": self.num_processes}
 
     def start_training(self, trainer: "pl.Trainer") -> None:
-        self._clean_logger(trainer)
         self.spawn(self.new_process, trainer, self.mp_queue, return_result=False)
         # reset optimizers, since main process is never used for training and thus does not have a valid optim state
         trainer.optimizers = []
 
     def start_evaluating(self, trainer: "pl.Trainer") -> None:
-        self._clean_logger(trainer)
         self.spawn(self.new_process, trainer, self.mp_queue, return_result=False)
 
     def start_predicting(self, trainer: "pl.Trainer") -> None:
-        self._clean_logger(trainer)
         self.spawn(self.new_process, trainer, self.mp_queue, return_result=False)
 
     def spawn(self, function: Callable, *args: Any, return_result: bool = True, **kwargs: Any) -> Optional[Any]:
@@ -420,16 +416,3 @@ def teardown(self) -> None:
             self.lightning_module.cpu()
             # clean up memory
             torch.cuda.empty_cache()
-
-    @staticmethod
-    def _clean_logger(trainer: "pl.Trainer") -> None:
-        loggers = trainer.logger._logger_iterable if isinstance(trainer.logger, LoggerCollection) else [trainer.logger]
-        for logger in loggers:
-            if isinstance(logger, TensorBoardLogger) and logger._experiment is not None:
-                rank_zero_warn(
-                    "When using `ddp_spawn`, the `TensorBoardLogger` experiment should be `None`. Setting it to `None`."
-                )
-                # the experiment class of `TensorBoard` holds a multiprocessing queue which can make ours hang.
-                # we want to make sure these are closed before we spawn our own threads.
-                # assuming nothing else references the experiment object, python should instantly `__del__` it.
-                logger._experiment = None

tests/helpers/runif.py

@@ -71,6 +71,7 @@ def __new__(
         deepspeed: bool = False,
         rich: bool = False,
         skip_49370: bool = False,
+        skip_hanging_spawn: bool = False,
         omegaconf: bool = False,
         **kwargs,
     ):
@@ -94,6 +95,7 @@ def __new__(
             deepspeed: Require that microsoft/DeepSpeed is installed.
             rich: Require that willmcgugan/rich is installed.
             skip_49370: Skip the test as it's impacted by https://github.com/pytorch/pytorch/issues/49370.
+            skip_hanging_spawn: Skip the test as it's impacted by hanging loggers on spawn.
             omegaconf: Require that omry/omegaconf is installed.
             **kwargs: Any :class:`pytest.mark.skipif` keyword arguments.
         """
@@ -180,6 +182,15 @@ def __new__(
             conditions.append(ge_3_9 and old_torch)
             reasons.append("Impacted by https://github.com/pytorch/pytorch/issues/49370")
 
+        if skip_hanging_spawn:
+            # strategy=ddp_spawn, accelerator=cpu, python>=3.8, torch<1.9 does not work
+            py_version = f"{sys.version_info.major}.{sys.version_info.minor}.{sys.version_info.micro}"
+            ge_3_8 = Version(py_version) >= Version("3.8")
+            torch_version = get_distribution("torch").version
+            old_torch = Version(torch_version) < Version("1.9")
+            conditions.append(ge_3_8 and old_torch)
+            reasons.append("Impacted by hanging DDP spawn")
+
         if omegaconf:
             conditions.append(not _OMEGACONF_AVAILABLE)
             reasons.append("omegaconf")

tests/loggers/test_all.py

@@ -329,7 +329,7 @@ def on_train_batch_start(self, trainer, pl_module, batch, batch_idx):
             assert pl_module.logger.experiment.something(foo="bar") is None
 
 
-@RunIf(skip_windows=True, skip_49370=True)
+@RunIf(skip_windows=True, skip_49370=True, skip_hanging_spawn=True)
 @pytest.mark.parametrize("logger_class", [CometLogger, CSVLogger, MLFlowLogger, TensorBoardLogger, TestTubeLogger])
 def test_logger_created_on_rank_zero_only(tmpdir, monkeypatch, logger_class):
     """Test that loggers get replaced by dummy loggers on global rank > 0."""

tests/loggers/test_tensorboard.py

@@ -24,7 +24,6 @@
 
 from pytorch_lightning import Trainer
 from pytorch_lightning.loggers import TensorBoardLogger
-from pytorch_lightning.loggers.base import LoggerCollection
 from pytorch_lightning.utilities.imports import _compare_version, _OMEGACONF_AVAILABLE
 from tests.helpers import BoringModel
 from tests.helpers.runif import RunIf
@@ -335,17 +334,3 @@ def test_tensorboard_missing_folder_warning(tmpdir, caplog):
         assert logger.version == 0
 
     assert "Missing logger folder:" in caplog.text
-
-
-@pytest.mark.parametrize("use_list", [False, True])
-def test_tensorboard_ddp_spawn_cleanup(use_list, tmpdir):
-    tensorboard_logger = TensorBoardLogger(save_dir=tmpdir)
-    assert tensorboard_logger._experiment is None
-    tensorboard_logger.experiment  # this property access will create the experiment
-    assert tensorboard_logger._experiment is not None
-    logger = [tensorboard_logger] if use_list else tensorboard_logger
-    trainer = Trainer(strategy="ddp_spawn", devices=2, accelerator="auto", logger=logger)
-    trainer.training_type_plugin._clean_logger(trainer)
-    if use_list:
-        assert isinstance(trainer.logger, LoggerCollection)
-    assert tensorboard_logger._experiment is None

tests/utilities/test_all_gather_grad.py

@@ -54,7 +54,7 @@ def _test_all_gather_ddp(rank, world_size):
     assert torch.allclose(grad2, tensor2.grad)
 
 
-@RunIf(skip_windows=True, skip_49370=True)
+@RunIf(skip_windows=True, skip_49370=True, skip_hanging_spawn=True)
 def test_all_gather_ddp_spawn():
     world_size = 3
     torch.multiprocessing.spawn(_test_all_gather_ddp, args=(world_size,), nprocs=world_size)