[Experimental] TorchFX PTQ backend (#2764)

### Changes

* Torch FX experimental PTQ backend is presented (MinMax, FBC)
* Torch metatypes are updated with new namespace: ATEN
* Some Torch metatypes are updated by new operations names 

### Reason for changes

To begin the Torch FX backend development

### Related tickets

141640

### Tests

* Resnet18 imagnette sanity test

nncf/common/factory.py

@@ -41,6 +41,10 @@ def create(model: TModel) -> NNCFGraph:
         if model_backend == BackendType.OPENVINO:
             from nncf.openvino.graph.nncf_graph_builder import GraphConverter
 
+            return GraphConverter.create_nncf_graph(model)
+        if model_backend == BackendType.TORCH_FX:
+            from nncf.experimental.torch.fx.nncf_graph_builder import GraphConverter
+
             return GraphConverter.create_nncf_graph(model)
         if model_backend == BackendType.TORCH:
             return model.nncf.get_graph()
@@ -72,6 +76,10 @@ def create(model: TModel, inplace: bool = False) -> ModelTransformer:
             from nncf.torch.model_transformer import PTModelTransformer
 
             return PTModelTransformer(model)
+        if model_backend == BackendType.TORCH_FX:
+            from nncf.experimental.torch.fx.model_transformer import FXModelTransformer
+
+            return FXModelTransformer(model)
         raise nncf.UnsupportedBackendError(
             "Cannot create backend-specific model transformer because {} is not supported!".format(model_backend.value)
         )
@@ -95,7 +103,7 @@ def create(model: TModel) -> Engine:
             from nncf.openvino.engine import OVNativeEngine
 
             return OVNativeEngine(model)
-        if model_backend == BackendType.TORCH:
+        if model_backend in (BackendType.TORCH, BackendType.TORCH_FX):
             from nncf.torch.engine import PTEngine
 
             return PTEngine(model)
@@ -151,6 +159,10 @@ def create(model: TModel, dataset: Dataset) -> aggregator.StatisticsAggregator:
             from nncf.torch.statistics.aggregator import PTStatisticsAggregator
 
             return PTStatisticsAggregator(dataset)
+        if model_backend == BackendType.TORCH_FX:
+            from nncf.experimental.torch.fx.statistics.aggregator import FXStatisticsAggregator
+
+            return FXStatisticsAggregator(dataset)
         raise nncf.UnsupportedBackendError(
             "Cannot create backend-specific statistics aggregator because {} is not supported!".format(
                 model_backend.value

nncf/common/graph/patterns/manager.py

@@ -47,7 +47,7 @@ def _get_backend_hw_patterns_map(backend: BackendType) -> Dict[HWFusedPatternNam
                 Dict[HWFusedPatternNames, Callable[[], GraphPattern]], OPENVINO_HW_FUSED_PATTERNS.registry_dict
             )
             return registry
-        if backend == BackendType.TORCH:
+        if backend in (BackendType.TORCH, BackendType.TORCH_FX):
             from nncf.torch.hardware.fused_patterns import PT_HW_FUSED_PATTERNS
 
             registry = cast(Dict[HWFusedPatternNames, Callable[[], GraphPattern]], PT_HW_FUSED_PATTERNS.registry_dict)
@@ -77,7 +77,7 @@ def _get_backend_ignored_patterns_map(
                 Dict[IgnoredPatternNames, Callable[[], GraphPattern]], OPENVINO_IGNORED_PATTERNS.registry_dict
             )
             return registry
-        if backend == BackendType.TORCH:
+        if backend in (BackendType.TORCH, BackendType.TORCH_FX):
             from nncf.torch.quantization.ignored_patterns import PT_IGNORED_PATTERNS
 
             registry = cast(Dict[IgnoredPatternNames, Callable[[], GraphPattern]], PT_IGNORED_PATTERNS.registry_dict)

nncf/common/utils/backend.py

@@ -20,6 +20,7 @@
 
 class BackendType(Enum):
     TORCH = "Torch"
+    TORCH_FX = "TorchFX"
     TENSORFLOW = "Tensorflow"
     ONNX = "ONNX"
     OPENVINO = "OpenVINO"
@@ -33,6 +34,7 @@ def get_available_backends() -> List[BackendType]:
     """
     frameworks = [
         ("torch", BackendType.TORCH),
+        ("torch.fx", BackendType.TORCH_FX),
         ("tensorflow", BackendType.TENSORFLOW),
         ("onnx", BackendType.ONNX),
         ("openvino.runtime", BackendType.OPENVINO),
@@ -51,14 +53,27 @@ def get_available_backends() -> List[BackendType]:
 
 def is_torch_model(model: TModel) -> bool:
     """
-    Returns True if the model is an instance of torch.nn.Module, otherwise False.
+    Returns True if the model is an instance of torch.nn.Module and not a torch.fx.GraphModule, otherwise False.
 
     :param model: A target model.
-    :return: True if the model is an instance of torch.nn.Module, otherwise False.
+    :return: True if the model is an instance of torch.nn.Module and not torch.fx.GraphModule, otherwise False.
     """
     import torch  # type: ignore
+    import torch.fx  # type: ignore
 
-    return isinstance(model, torch.nn.Module)
+    return not isinstance(model, torch.fx.GraphModule) and isinstance(model, torch.nn.Module)
+
+
+def is_torch_fx_model(model: TModel) -> bool:
+    """
+    Returns True if the model is an instance of torch.fx.GraphModule, otherwise False.
+
+    :param model: A target model.
+    :return: True if the model is an instance of torch.fx.GraphModule, otherwise False.
+    """
+    import torch.fx
+
+    return isinstance(model, torch.fx.GraphModule)
 
 
 def is_tensorflow_model(model: TModel) -> bool:
@@ -118,6 +133,9 @@ def get_backend(model: TModel) -> BackendType:
     """
     available_backends = get_available_backends()
 
+    if BackendType.TORCH_FX in available_backends and is_torch_fx_model(model):
+        return BackendType.TORCH_FX
+
     if BackendType.TORCH in available_backends and is_torch_model(model):
         return BackendType.TORCH
 

nncf/experimental/torch/fx/__init__.py

@@ -0,0 +1,10 @@
+# Copyright (c) 2024 Intel Corporation
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#      http://www.apache.org/licenses/LICENSE-2.0
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.

nncf/experimental/torch/fx/commands.py

@@ -0,0 +1,37 @@
+# Copyright (c) 2024 Intel Corporation
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#      http://www.apache.org/licenses/LICENSE-2.0
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from typing import Callable, Union
+
+import torch.fx
+
+from nncf.common.graph.transformations.commands import Command
+from nncf.common.graph.transformations.commands import TransformationPriority
+from nncf.common.graph.transformations.commands import TransformationType
+
+
+class FXApplyTransformationCommand(Command):
+    """
+    Command to apply given transformation to a model.
+    """
+
+    def __init__(
+        self,
+        transformation_fn: Callable[[torch.fx.GraphModule], None],
+        priority: Union[TransformationPriority, int] = TransformationPriority.DEFAULT_PRIORITY,
+    ):
+        """
+        :param transformation_fn: Target transformation function.
+        :param priority: Transformation priority.
+        """
+        super().__init__(TransformationType.INSERT)
+        self.tranformation_fn = transformation_fn
+        self.priority = priority

nncf/experimental/torch/fx/model_transformer.py

@@ -0,0 +1,116 @@
+# Copyright (c) 2024 Intel Corporation
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#      http://www.apache.org/licenses/LICENSE-2.0
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from collections import defaultdict
+from typing import List
+
+import torch
+import torch.fx
+from torch.fx.passes.split_utils import split_by_tags
+
+from nncf.common.graph.model_transformer import ModelTransformer
+from nncf.experimental.torch.fx.commands import FXApplyTransformationCommand
+from nncf.torch.graph.transformations.commands import PTModelExtractionCommand
+from nncf.torch.graph.transformations.layout import PTTransformationLayout
+
+
+class FXModelTransformer(ModelTransformer):
+    """
+    Applies transformations upon Torch FX model.
+    """
+
+    def __init__(self, model: torch.fx.GraphModule):
+        super().__init__(model)
+
+        self._command_transformation_ordered_pairs = [
+            (FXApplyTransformationCommand, self._apply_transformation),
+            (PTModelExtractionCommand, self._apply_model_extraction),
+        ]
+
+    def transform(self, transformation_layout: PTTransformationLayout) -> torch.fx.GraphModule:
+        """
+        Transforms the target model according to given transformation layout.
+
+        :param transformation_layout: Given transformation layout.
+        :return: Target model transformered according to the given transformation layout.
+        """
+        # TODO(dlyakhov): Manage priorities of transformations.
+        transformations = transformation_layout.transformations
+        aggregated_transformations = defaultdict(list)
+        for transformation in transformations:
+            aggregated_transformations[transformation.__class__].append(transformation)
+
+        model = self._model
+        for transformation_cls, transformation_fn in self._command_transformation_ordered_pairs:
+            transformations = aggregated_transformations[transformation_cls]
+            if transformations:
+                model = transformation_fn(model, transformations)
+
+        # Do not use model.graph.eliminate_dead_code()
+        # because the computational statistics code
+        # is interpolated as dead code.
+        model.recompile()
+        return model
+
+    @staticmethod
+    def _apply_model_extraction(
+        model: torch.fx.GraphModule,
+        transformations: List[PTModelExtractionCommand],
+    ) -> torch.fx.GraphModule:
+        """
+        Returns a submodel extracted from the given model by the given transformation.
+
+        :param model: Given model.
+        :param transformations: List of one transformation which specifies
+            how to retrieve a submodule from the model. In case list contains
+            more than one element this function raises an assert.
+        :return: Returns a submodel extracted from the given model by the given transformation.
+        """
+        transformation = transformations[-1]
+        assert len(transformation.input_node_names) == 1
+        assert transformation.input_node_names == transformation.output_node_names
+        node_name = transformation.input_node_names[0]
+
+        tags = ["before", "extracted", "after"]
+        i = 0
+        for node in model.graph.nodes:
+            if node.name == node_name:
+                node.tag = tags[1]
+                weights = [node.all_input_nodes[1]]
+                while weights:
+                    w_node = weights.pop()
+                    assert w_node.tag in tags[0:2]
+                    w_node.tag = tags[1]
+                    weights.extend(w_node.all_input_nodes)
+                i = 2
+                continue
+            node.tag = tags[i]
+
+        # TODO(dlyakhov): reduce memory consumption by
+        # more optimal splitting implementation.
+        splitted_gm = split_by_tags(model, tags)
+        return splitted_gm.extracted
+
+    @staticmethod
+    def _apply_transformation(
+        model: torch.fx.GraphModule,
+        transformations: List[FXApplyTransformationCommand],
+    ) -> torch.fx.GraphModule:
+        """
+        Applies transformations to the given model.
+
+        :param model: Target model.
+        :param transformations: Transformations to apply to the model.
+        :return: Target model after all transformations were applied.
+        """
+        for transformation in transformations:
+            transformation.tranformation_fn(model)
+        return model