Free outputs callback

composer/callbacks/__init__.py

@@ -10,6 +10,7 @@
 from composer.callbacks.checkpoint_saver import CheckpointSaver
 from composer.callbacks.early_stopper import EarlyStopper
 from composer.callbacks.export_for_inference import ExportForInferenceCallback
+from composer.callbacks.free_outputs import FreeOutputs
 from composer.callbacks.generate import Generate
 from composer.callbacks.health_checker import HealthChecker
 from composer.callbacks.image_visualizer import ImageVisualizer
@@ -38,4 +39,5 @@
     'RuntimeEstimator',
     'SystemMetricsMonitor',
     'Generate',
+    'FreeOutputs',
 ]

composer/callbacks/free_outputs.py

@@ -0,0 +1,16 @@
+# Copyright 2022 MosaicML Composer authors
+# SPDX-License-Identifier: Apache-2.0
+
+"""Free train metrics."""
+
+import torch
+
+from composer.core import Callback, State
+from composer.loggers import Logger
+
+
+class FreeOutputs(Callback):
+    """Free train metrics on AFTER_LOSS to reduce peak memory usage if not using train metrics."""
+
+    def after_loss(self, state: State, logger: Logger) -> None:
+        state.outputs = torch.Tensor()

composer/callbacks/generate.py

@@ -2,6 +2,7 @@
 # SPDX-License-Identifier: Apache-2.0
 
 """Periodically log generations from a set of prompts."""
+
 from typing import Any, List, Optional, Union, cast
 
 from composer.callbacks.utils import create_interval_scheduler

tests/callbacks/callback_settings.py

@@ -11,8 +11,9 @@
 import composer.loggers
 import composer.profiler
 from composer import Callback
-from composer.callbacks import (EarlyStopper, ExportForInferenceCallback, Generate, HealthChecker, ImageVisualizer,
-                                MemoryMonitor, MLPerfCallback, SpeedMonitor, SystemMetricsMonitor, ThresholdStopper)
+from composer.callbacks import (EarlyStopper, ExportForInferenceCallback, FreeOutputs, Generate, HealthChecker,
+                                ImageVisualizer, MemoryMonitor, MLPerfCallback, SpeedMonitor, SystemMetricsMonitor,
+                                ThresholdStopper)
 from composer.loggers import (CometMLLogger, ConsoleLogger, LoggerDestination, MLFlowLogger, ProgressBarLogger,
                               RemoteUploaderDownloader, TensorboardLogger, WandBLogger)
 from composer.models.base import ComposerModel
@@ -223,5 +224,8 @@ def get_cb_model_and_datasets(cb: Callback,
             )
         return (configure_tiny_gpt2_hf_model(), dummy_gpt_lm_dataloader(size=dl_size),
                 dummy_gpt_lm_dataloader(size=dl_size))
-    return (SimpleModel(), DataLoader(RandomClassificationDataset(size=dl_size), **default_dl_kwargs),
+    model = SimpleModel()
+    if isinstance(cb, FreeOutputs):
+        model.get_metrics = lambda is_train=False: {}
+    return (model, DataLoader(RandomClassificationDataset(size=dl_size), **default_dl_kwargs),
             DataLoader(RandomClassificationDataset(size=dl_size), **default_dl_kwargs))