[OVQuantizer] Apply Fixes and Integrate into the Llama Example Workflow

backends/openvino/quantizer/__init__.py

@@ -1,3 +1,3 @@
-from .quantizer import OpenVINOQuantizer, quantize_model
+from .quantizer import OpenVINOQuantizer, quantize_model, QuantizationMode
 
-__all__ = ["OpenVINOQuantizer", "quantize_model"]
+__all__ = ["OpenVINOQuantizer", "quantize_model", "QuantizationMode"]

backends/openvino/quantizer/observers.py

@@ -0,0 +1,198 @@
+# Copyright (c) Intel Corporation
+#
+# Licensed under the BSD License (the "License"); you may not use this file
+# except in compliance with the License. See the license file found in the
+# LICENSE file in the root directory of this source tree.
+
+# mypy: disable-error-code=import-not-found
+
+from abc import ABC, abstractmethod
+from typing import Optional, Tuple
+
+import torch
+
+from nncf.experimental.torch.fx.node_utils import (  # type: ignore[import-untyped]
+    get_tensor_constant_from_node,
+)
+from nncf.experimental.torch.fx.transformations import (  # type: ignore[import-untyped]
+    constant_update,
+    module_insertion,
+    node_removal,
+)
+from nncf.quantization.algorithms.weight_compression.config import (  # type: ignore[import-untyped]
+    WeightCompressionParameters,
+)
+from nncf.quantization.algorithms.weight_compression.weight_lowering import (  # type: ignore[import-untyped]
+    do_integer_quantization,
+)
+from nncf.tensor.tensor import Tensor as NNCFTensor  # type: ignore[import-untyped]
+from nncf.torch.graph.transformations.commands import (  # type: ignore[import-untyped]
+    PTTargetPoint,
+    TargetType,
+)
+from nncf.torch.quantization.layers import (  # type: ignore[import-untyped]
+    BaseWeightsDecompressor,
+    INT4AsymmetricWeightsDecompressor,
+    INT4SymmetricWeightsDecompressor,
+    INT8AsymmetricWeightsDecompressor,
+    INT8SymmetricWeightsDecompressor,
+)
+from torchao.quantization.pt2e import ObserverBase
+
+
+class WeightObserverBase(ObserverBase, ABC):
+    """
+    Base implementation of an NNCF observer that defines the rules for compressing layer weights into the OpenVINO representation.
+    """
+
+    def __init__(
+        self,
+        wc_param: WeightCompressionParameters,
+        dtype: torch.dtype,
+        **kwargs,
+    ) -> None:
+        """
+        :param wc_param: Weight compression parameters container.
+        :param dtype: target dtype for the quantization.
+        """
+        super().__init__(dtype=dtype, is_dynamic=False)
+        self.wc_param = wc_param
+
+    def calculate_qparams(  # type: ignore[override]
+        self,
+        weight: torch.Tensor,
+    ) -> Tuple[torch.Tensor, torch.Tensor, Optional[torch.Tensor]]:
+        """
+        Calculates quantization parameters: quantized weight, quantization scale and quantization zero point.
+
+        :param weight: FP weight to be used for calculating qparams.
+        :return: A tuple containing the quantized weight, quantization scale and quantization zero point.
+        """
+        wc_param = self.get_wc_param()
+        wc_config = wc_param.compression_config
+        reduction_axes = wc_param.reduction_axes
+        q_weight, scale, zp = do_integer_quantization(
+            NNCFTensor(weight), wc_config, reduction_axes=reduction_axes
+        )
+        zp = zp.data if zp is not None else None
+        return q_weight.data, scale.data, zp
+
+    def forward(self, x: torch.Tensor) -> torch.Tensor:
+        return x
+
+    def convert(
+        self, model: torch.fx.GraphModule, observer_node: torch.fx.Node
+    ) -> None:
+        """
+        Replaces the given observer node from the given model with a quantized 
+        weight and a OpenVINO specific decompression module.
+
+        :param model: A `torch.fx.GraphModule` representing the statically traced model
+                    with observer nodes attached and calibrated.
+        :param observer_node: The `torch.fx.Node` corresponding to the observer module for
+                            the weight that is being transformed into a compressed representation.
+        """
+        weight_node = observer_node.args[0]
+        original_weight = get_tensor_constant_from_node(weight_node, model)
+        q_weight, scale, zero_point = self.calculate_qparams(
+            original_weight
+        )
+
+        decompressor = self._create_decompressor(
+            scale, zero_point, q_weight, original_weight
+        )
+        packed_q_weight = decompressor.pack_weight(q_weight)
+
+        # Weight port id is 0 since observer is inserted for a single weight only.
+        constant_update(model, observer_node, packed_q_weight, input_port_id=0)
+
+        compressed_weight_name = observer_node.all_input_nodes[0].name
+        decompressor_suffix = "_".join(
+            compressed_weight_name.replace(".", "_").split("_")[:-2]
+        )
+        decompressor_name = f"{decompressor.quantization_mode}_weights_decompressor_{decompressor_suffix}"
+
+        module_insertion(
+            model,
+            decompressor,
+            [
+                PTTargetPoint(
+                    TargetType.OPERATOR_POST_HOOK,
+                    target_node_name=compressed_weight_name,
+                )
+            ],
+            decompressor_name,
+        )
+        node_removal(model, observer_node, 0)
+
+    @abstractmethod
+    def _create_decompressor(
+        self,
+        scale: torch.Tensor,
+        zero_point: Optional[torch.Tensor],
+        q_weight: torch.Tensor,
+        original_weight: torch.Tensor,
+    ) -> BaseWeightsDecompressor:
+        """
+        Returns a respective NNCF decompressor for different types of quantization.
+
+        :param scale: Calculated scale quantization parameter.
+        :param zero_point: Calculated zero_point quantization parameter.
+        :param q_weight: Calculated quantized weight.
+        :param original_weight: FP weight.
+        :return: NNCF observer according to the qmode which creates the decompression subgraph supported by OpenVINO.
+        """
+
+    def get_wc_param(self) -> WeightCompressionParameters:
+        """
+        Returns a respective NNCF Weight Compression Config.
+
+        :return: Weight compression config with the compression information such as qmode, group_size etc.
+        """
+        return self.wc_param
+
+class INT4WeightObserver(WeightObserverBase):
+    """
+    OpenVINO INT4 Weight Compression observer.
+    """
+
+    def _create_decompressor(
+        self,
+        scale: torch.Tensor,
+        zero_point: Optional[torch.Tensor],
+        q_weight: torch.Tensor,
+        original_weight: torch.Tensor,
+    ) -> BaseWeightsDecompressor:
+        if zero_point is not None:
+            return INT4AsymmetricWeightsDecompressor(
+                scale,
+                zero_point,
+                q_weight.shape,
+                original_weight.shape,
+                original_weight.dtype,
+            )
+        else:
+            return INT4SymmetricWeightsDecompressor(
+                scale, q_weight.shape, original_weight.shape, original_weight.dtype
+            )
+
+
+class INT8WeightObserver(WeightObserverBase):
+    """
+    OpenVINO INT8 Weight Compression per channel observer.
+    """
+
+    def _create_decompressor(
+        self,
+        scale: torch.Tensor,
+        zero_point: Optional[torch.Tensor],
+        q_weight: torch.Tensor,
+        original_weight: torch.Tensor,
+    ) -> BaseWeightsDecompressor:
+        if zero_point is not None:
+            return INT8AsymmetricWeightsDecompressor(
+                scale, zero_point, original_weight.dtype
+            )
+        else:
+            return INT8SymmetricWeightsDecompressor(scale, original_weight.dtype)
+