Allow GradientAccumulationPlugin to be configured from AcceleratorConfig (#29589)

* add gradient_accumulation_kwargs to AcceleratorConfig

* add suggestions from @muellerzr to docstrings, new behavior and tests

* Documentation suggestions from @muellerz
Co-authored-by: Zach Mueller <muellerzr@gmail.com>

* addressed @muellerzr comments regarding tests and test utils

* moved accelerate version to top of file.

* @muellerzr's variable fix
Co-authored-by: Zach Mueller <muellerzr@gmail.com>

* address @amyeroberts. fix tests and docstrings

* address @amyeroberts additional suggestions

---------
Co-authored-by: Yu Chin Fabian Lim <flim@sg.ibm.com>
Co-authored-by: Zach Mueller <muellerzr@gmail.com>

src/transformers/testing_utils.py

@@ -52,6 +52,7 @@ from .integrations import (
 )
 from .integrations.deepspeed import is_deepspeed_available
 from .utils import (
+    ACCELERATE_MIN_VERSION,
     is_accelerate_available,
     is_apex_available,
     is_aqlm_available,
@@ -365,11 +366,13 @@ def require_nltk(test_case):
     return unittest.skipUnless(is_nltk_available(), "test requires NLTK")(test_case)
 
 
-def require_accelerate(test_case):
+def require_accelerate(test_case, min_version: str = ACCELERATE_MIN_VERSION):
     """
     Decorator marking a test that requires accelerate. These tests are skipped when accelerate isn't installed.
     """
-    return unittest.skipUnless(is_accelerate_available(), "test requires accelerate")(test_case)
+    return unittest.skipUnless(
+        is_accelerate_available(min_version), f"test requires accelerate version >= {min_version}"
+    )(test_case)
 
 
 def require_fsdp(test_case, min_version: str = "1.12.0"):

src/transformers/trainer.py

@@ -4324,8 +4324,23 @@ class Trainer:
             self.repo.git_push()
 
     def create_accelerator_and_postprocess(self):
-        grad_acc_kwargs = {"num_steps": self.args.gradient_accumulation_steps}
+        grad_acc_kwargs = {}
+        if is_accelerate_available("0.28.0") and self.args.accelerator_config.gradient_accumulation_kwargs is not None:
+            grad_acc_kwargs = self.args.accelerator_config.gradient_accumulation_kwargs
+
+        # check if num_steps is attempted to be passed in gradient_accumulation_kwargs
+        if "num_steps" in grad_acc_kwargs and self.args.gradient_accumulation_steps > 1:
+            # raise because we do not know which setting is intended.
+            raise ValueError(
+                "The `AcceleratorConfig`'s `num_steps` is set but `gradient_accumulation_steps` is greater than 1 in the passed `TrainingArguments`"
+                "If using the passed `AcceleratorConfig` is desired, do not set the `TrainingArguments` `gradient_accumulation_steps`."
+            )
+        elif "num_steps" not in grad_acc_kwargs:
+            # take the gradient_accumulation_steps setting from TrainingArguments.
+            grad_acc_kwargs["num_steps"] = self.args.gradient_accumulation_steps
+
         grad_acc_kwargs["sync_with_dataloader"] = False
+
         gradient_accumulation_plugin = GradientAccumulationPlugin(**grad_acc_kwargs)
 
         accelerator_config = self.args.accelerator_config.to_dict()
@@ -4337,6 +4352,8 @@ class Trainer:
                 even_batches=accelerator_config.pop("even_batches"),
                 use_seedable_sampler=accelerator_config.pop("use_seedable_sampler"),
             )
+            # this would have been updated above, no need for it anymore
+            accelerator_config.pop("gradient_accumulation_kwargs")
         args = {
             "deepspeed_plugin": self.args.deepspeed_plugin,
             "gradient_accumulation_plugin": gradient_accumulation_plugin,

src/transformers/trainer_pt_utils.py

@@ -1185,6 +1185,15 @@ class AcceleratorConfig:
             training results are fully reproducable using a different sampling technique. While seed-to-seed results
             may differ, on average the differences are neglible when using multiple different seeds to compare. Should
             also be ran with [`~utils.set_seed`] for the best results.
+        gradient_accumulation_kwargs (`dict`, *optional*):
+            Additional kwargs to configure gradient accumulation, see [`accelerate.utils.GradientAccumulationPlugin`].
+            Any of the following (optional) keys are acceptable:
+              num_steps (`int`): Will take precedence over [`~.TrainingArguments.gradient_accumulation_steps`] if
+                the latter is set to 1, otherwise an exception will be raised.
+              adjust_scheduler (`bool`): Whether to adjust the scheduler steps to account for [`~.TrainingArguments.gradient_accumulation_steps`].
+                The [`accelerate.utils.GradientAccumulationPlugin`] default is `True`.
+              sync_each_batch (`bool`): Whether to synchronize the gradients at each data batch.
+                The [`accelerate.utils.GradientAccumulationPlugin`] default is `False`.
 
     """
 
@@ -1223,6 +1232,19 @@ class AcceleratorConfig:
             "multiple different seeds to compare. Should also be ran with [`~utils.set_seed`] for the best results."
         },
     )
+    gradient_accumulation_kwargs: Optional[Dict] = field(
+        default=None,
+        metadata={
+            "help": "Additional kwargs to configure gradient accumulation, see [`accelerate.utils.GradientAccumulationPlugin`]. "
+            "Any of the following (optional) keys are acceptable: "
+            "  num_steps (`int`): Will take precedence over [`~.TrainingArguments.gradient_accumulation_steps`] if "
+            "    the latter is set to 1, otherwise an exception will be raised. "
+            "  adjust_scheduler (`bool`): Whether to adjust the scheduler steps to account for [`~.TrainingArguments.gradient_accumulation_steps`]. "
+            "    The [`accelerate.utils.GradientAccumulationPlugin`] default is `True`. "
+            "  sync_each_batch (`bool`): Whether to synchronize the gradients at each data batch. "
+            "    The [`accelerate.utils.GradientAccumulationPlugin`] default is `False`."
+        },
+    )
 
     @classmethod
     def from_json_file(cls, json_file):

src/transformers/utils/import_utils.py

@@ -805,9 +805,7 @@ def is_protobuf_available():
 
 
 def is_accelerate_available(min_version: str = ACCELERATE_MIN_VERSION):
-    if min_version is not None:
     return _accelerate_available and version.parse(_accelerate_version) >= version.parse(min_version)
-    return _accelerate_available
 
 
 def is_fsdp_available(min_version: str = FSDP_MIN_VERSION):

tests/trainer/test_trainer.py

@@ -24,6 +24,7 @@ import subprocess
 import sys
 import tempfile
 import unittest
+from functools import partial
 from itertools import product
 from pathlib import Path
 from typing import Dict, List
@@ -92,6 +93,7 @@ from transformers.utils import (
     SAFE_WEIGHTS_NAME,
     WEIGHTS_INDEX_NAME,
     WEIGHTS_NAME,
+    is_accelerate_available,
     is_apex_available,
     is_bitsandbytes_available,
     is_safetensors_available,
@@ -127,6 +129,9 @@ if is_torch_available():
     if is_safetensors_available():
         import safetensors.torch
 
+# for version specific tests in TrainerIntegrationTest
+require_accelerate_version_min_0_28 = partial(require_accelerate, min_version="0.28")
+GRAD_ACCUM_KWARGS_VERSION_AVAILABLE = is_accelerate_available("0.28")
 
 PATH_SAMPLE_TEXT = f"{get_tests_dir()}/fixtures/sample_text.txt"
 
@@ -2877,6 +2882,10 @@ class TrainerIntegrationTest(TestCasePlus, TrainerIntegrationCommon):
             self.assertEqual(trainer.accelerator.even_batches, True)
             self.assertEqual(trainer.accelerator.use_seedable_sampler, True)
 
+            if GRAD_ACCUM_KWARGS_VERSION_AVAILABLE:
+                # gradient accumulation kwargs configures gradient_state
+                self.assertNotIn("sync_each_batch", trainer.accelerator.gradient_state.plugin_kwargs)
+
     def test_accelerator_config_from_dict(self):
         # Checks that accelerator kwargs can be passed through
         # and the accelerator is initialized respectively
@@ -2885,15 +2894,19 @@ class TrainerIntegrationTest(TestCasePlus, TrainerIntegrationCommon):
             model = RegressionPreTrainedModel(config)
             eval_dataset = SampleIterableDataset()
 
-            # Leaves all options as something *not* basic
-            args = RegressionTrainingArguments(
-                output_dir=tmp_dir,
-                accelerator_config={
+            accelerator_config = {
                 "split_batches": True,
                 "dispatch_batches": True,
                 "even_batches": False,
                 "use_seedable_sampler": True,
-                },
+            }
+            if GRAD_ACCUM_KWARGS_VERSION_AVAILABLE:
+                accelerator_config["gradient_accumulation_kwargs"] = {"sync_each_batch": True}
+
+            # Leaves all options as something *not* basic
+            args = RegressionTrainingArguments(
+                output_dir=tmp_dir,
+                accelerator_config=accelerator_config,
             )
             trainer = Trainer(model=model, args=args, eval_dataset=eval_dataset)
             self.assertEqual(trainer.accelerator.split_batches, True)
@@ -2901,6 +2914,9 @@ class TrainerIntegrationTest(TestCasePlus, TrainerIntegrationCommon):
             self.assertEqual(trainer.accelerator.even_batches, False)
             self.assertEqual(trainer.accelerator.use_seedable_sampler, True)
 
+            if GRAD_ACCUM_KWARGS_VERSION_AVAILABLE:
+                self.assertEqual(trainer.accelerator.gradient_state.plugin_kwargs["sync_each_batch"], True)
+
     def test_accelerator_config_from_yaml(self):
         # Checks that accelerator kwargs can be passed through
         # and the accelerator is initialized respectively
@@ -2913,6 +2929,8 @@ class TrainerIntegrationTest(TestCasePlus, TrainerIntegrationCommon):
                     "even_batches": False,
                     "use_seedable_sampler": False,
                 }
+                if GRAD_ACCUM_KWARGS_VERSION_AVAILABLE:
+                    accelerator_config["gradient_accumulation_kwargs"] = {"sync_each_batch": True}
                 json.dump(accelerator_config, f)
             config = RegressionModelConfig(a=1.5, b=2.5)
             model = RegressionPreTrainedModel(config)
@@ -2926,11 +2944,18 @@ class TrainerIntegrationTest(TestCasePlus, TrainerIntegrationCommon):
             self.assertEqual(trainer.accelerator.even_batches, False)
             self.assertEqual(trainer.accelerator.use_seedable_sampler, False)
 
+            if GRAD_ACCUM_KWARGS_VERSION_AVAILABLE:
+                self.assertEqual(trainer.accelerator.gradient_state.plugin_kwargs["sync_each_batch"], True)
+
     def test_accelerator_config_from_dataclass(self):
         # Checks that accelerator kwargs can be passed through
         # and the accelerator is initialized respectively
+
         accelerator_config = AcceleratorConfig(
-            split_batches=True, dispatch_batches=True, even_batches=False, use_seedable_sampler=False
+            split_batches=True,
+            dispatch_batches=True,
+            even_batches=False,
+            use_seedable_sampler=False,
         )
         config = RegressionModelConfig(a=1.5, b=2.5)
         model = RegressionPreTrainedModel(config)
@@ -2943,6 +2968,35 @@ class TrainerIntegrationTest(TestCasePlus, TrainerIntegrationCommon):
             self.assertEqual(trainer.accelerator.even_batches, False)
             self.assertEqual(trainer.accelerator.use_seedable_sampler, False)
 
+    @require_accelerate_version_min_0_28
+    def test_accelerate_config_from_dataclass_grad_accum(self):
+        # Checks that accelerator kwargs can be passed through
+        # and the accelerator is initialized respectively
+
+        grad_acc_kwargs = {
+            "num_steps": 10,
+            "adjust_scheduler": False,
+            "sync_with_dataloader": False,
+            "sync_each_batch": True,
+        }
+        accelerator_config = AcceleratorConfig(
+            split_batches=True,
+            dispatch_batches=True,
+            even_batches=False,
+            use_seedable_sampler=False,
+            gradient_accumulation_kwargs=grad_acc_kwargs,
+        )
+        config = RegressionModelConfig(a=1.5, b=2.5)
+        model = RegressionPreTrainedModel(config)
+        eval_dataset = SampleIterableDataset()
+        with tempfile.TemporaryDirectory() as tmp_dir:
+            args = RegressionTrainingArguments(output_dir=tmp_dir, accelerator_config=accelerator_config)
+            trainer = Trainer(model=model, args=args, eval_dataset=eval_dataset)
+            self.assertEqual(trainer.accelerator.gradient_state.plugin_kwargs["num_steps"], 10)
+            self.assertEqual(trainer.accelerator.gradient_state.plugin_kwargs["adjust_scheduler"], False)
+            self.assertEqual(trainer.accelerator.gradient_state.plugin_kwargs["sync_with_dataloader"], False)
+            self.assertEqual(trainer.accelerator.gradient_state.plugin_kwargs["sync_each_batch"], True)
+
     def test_accelerator_config_from_partial(self):
         # Checks that accelerator kwargs can be passed through
         # and the accelerator is initialized respectively
@@ -3014,6 +3068,44 @@ class TrainerIntegrationTest(TestCasePlus, TrainerIntegrationCommon):
                 trainer = Trainer(model=model, args=args, eval_dataset=eval_dataset)
                 self.assertEqual(trainer.accelerator.split_batches, True)
 
+    @require_accelerate_version_min_0_28
+    def test_accelerator_config_from_dict_grad_accum_num_steps(self):
+        with tempfile.TemporaryDirectory() as tmp_dir:
+            config = RegressionModelConfig(a=1.5, b=2.5)
+            model = RegressionPreTrainedModel(config)
+            eval_dataset = SampleIterableDataset()
+
+            # case - TrainingArguments.gradient_accumulation_steps == 1
+            #      - gradient_accumulation_kwargs['num_steps] == 1
+            # results in grad accum set to 1
+            args = RegressionTrainingArguments(
+                output_dir=tmp_dir,
+                gradient_accumulation_steps=1,
+                accelerator_config={
+                    "gradient_accumulation_kwargs": {
+                        "num_steps": 1,
+                    }
+                },
+            )
+            trainer = Trainer(model=model, args=args, eval_dataset=eval_dataset)
+            self.assertEqual(trainer.accelerator.gradient_state.plugin_kwargs["num_steps"], 1)
+
+            # case - TrainingArguments.gradient_accumulation_steps > 1
+            #      - gradient_accumulation_kwargs['num_steps] specified
+            # results in exception raised
+            args = RegressionTrainingArguments(
+                output_dir=tmp_dir,
+                gradient_accumulation_steps=2,
+                accelerator_config={
+                    "gradient_accumulation_kwargs": {
+                        "num_steps": 10,
+                    }
+                },
+            )
+            with self.assertRaises(Exception) as context:
+                trainer = Trainer(model=model, args=args, eval_dataset=eval_dataset)
+            self.assertTrue("The `AcceleratorConfig`'s `num_steps` is set but" in str(context.exception))
+
 
 @require_torch
 @is_staging_test