Convert and Optimize YOLOv8 with OpenVINO™#
This Jupyter notebook can be launched after a local installation only.
The YOLOv8 algorithm developed by Ultralytics is a cutting-edge, state-of-the-art (SOTA) model that is designed to be fast, accurate, and easy to use, making it an excellent choice for a wide range of object detection, image segmentation, and image classification tasks. More details about its realization can be found in the original model repository.
This tutorial demonstrates step-by-step instructions on how to run apply quantization with accuracy control to PyTorch YOLOv8. The advanced quantization flow allows to apply 8-bit quantization to the model with control of accuracy metric. This is achieved by keeping the most impactful operations within the model in the original precision. The flow is based on the Basic 8-bit quantization and has the following differences:
Besides the calibration dataset, a validation dataset is required to compute the accuracy metric. Both datasets can refer to the same data in the simplest case.
Validation function, used to compute accuracy metric is required. It can be a function that is already available in the source framework or a custom function.
Since accuracy validation is run several times during the quantization process, quantization with accuracy control can take more time than the Basic 8-bit quantization flow.
The resulted model can provide smaller performance improvement than the Basic 8-bit quantization flow because some of the operations are kept in the original precision.
NOTE: Currently, 8-bit quantization with accuracy control in NNCF is available only for models in OpenVINO representation.
The steps for the quantization with accuracy control are described below.
Table of contents:
Installation Instructions#
This is a self-contained example that relies solely on its own code.
We recommend running the notebook in a virtual environment. You only need a Jupyter server to start. For details, please refer to Installation Guide.
Prerequisites#
Install necessary packages.
%pip install -q "openvino>=2024.0.0"
%pip install -q "nncf>=2.9.0"
%pip install -q "ultralytics==8.1.42" tqdm --extra-index-url https://download.pytorch.org/whl/cpu
Get Pytorch model and OpenVINO IR model#
Generally, PyTorch models represent an instance of the
torch.nn.Module
class, initialized by a state dictionary with model weights. We will use
the YOLOv8 nano model (also known as yolov8n
) pre-trained on a COCO
dataset, which is available in this
repo. Similar steps are
also applicable to other YOLOv8 models. Typical steps to obtain a
pre-trained model:
Create an instance of a model class.
Load a checkpoint state dict, which contains the pre-trained model weights.
In this case, the creators of the model provide an API that enables converting the YOLOv8 model to ONNX and then to OpenVINO IR. Therefore, we do not need to do these steps manually.
import os
from pathlib import Path
from ultralytics import YOLO
from ultralytics.cfg import get_cfg
from ultralytics.data.utils import check_det_dataset
from ultralytics.engine.validator import BaseValidator as Validator
from ultralytics.utils import DEFAULT_CFG
from ultralytics.utils import ops
from ultralytics.utils.metrics import ConfusionMatrix
ROOT = os.path.abspath("")
MODEL_NAME = "yolov8n-seg"
model = YOLO(f"{ROOT}/{MODEL_NAME}.pt")
args = get_cfg(cfg=DEFAULT_CFG)
args.data = "coco128-seg.yaml"
# Fetch the notebook utils script from the openvino_notebooks repo
import requests
r = requests.get(
url="https://raw.githubusercontent.com/openvinotoolkit/openvino_notebooks/latest/utils/notebook_utils.py",
)
open("notebook_utils.py", "w").write(r.text)
from notebook_utils import download_file, device_widget
from zipfile import ZipFile
from ultralytics.data.utils import DATASETS_DIR
DATA_URL = "https://www.ultralytics.com/assets/coco128-seg.zip"
CFG_URL = "https://raw.githubusercontent.com/ultralytics/ultralytics/8ebe94d1e928687feaa1fee6d5668987df5e43be/ultralytics/datasets/coco128-seg.yaml" # last compatible format with ultralytics 8.0.43
OUT_DIR = DATASETS_DIR
DATA_PATH = OUT_DIR / "coco128-seg.zip"
CFG_PATH = OUT_DIR / "coco128-seg.yaml"
download_file(DATA_URL, DATA_PATH.name, DATA_PATH.parent)
download_file(CFG_URL, CFG_PATH.name, CFG_PATH.parent)
if not (OUT_DIR / "coco128/labels").exists():
with ZipFile(DATA_PATH, "r") as zip_ref:
zip_ref.extractall(OUT_DIR)
'/home/maleksandr/test_notebooks/ultrali/datasets/coco128-seg.zip' already exists.
/home/maleksandr/test_notebooks/ultrali/datasets/coco128-seg.yaml: 0%| | 0.00/0.98k [00:00<?, ?B/s]
Load model.
import openvino as ov
model_path = Path(f"{ROOT}/{MODEL_NAME}_openvino_model/{MODEL_NAME}.xml")
if not model_path.exists():
model.export(format="openvino", dynamic=True, half=False)
ov_model = ov.Core().read_model(model_path)
Define validator and data loader#
The original model repository uses a Validator
wrapper, which
represents the accuracy validation pipeline. It creates dataloader and
evaluation metrics and updates metrics on each data batch produced by
the dataloader. Besides that, it is responsible for data preprocessing
and results postprocessing. For class initialization, the configuration
should be provided. We will use the default setup, but it can be
replaced with some parameters overriding to test on custom data. The
model has connected the ValidatorClass
method, which creates a
validator class instance.
from ultralytics.data.converter import coco80_to_coco91_class
validator = model.task_map[model.task]["validator"](args=args)
validator.data = check_det_dataset(args.data)
validator.stride = 3
data_loader = validator.get_dataloader(OUT_DIR / "coco128-seg", 1)
validator.is_coco = True
validator.class_map = coco80_to_coco91_class()
validator.names = model.model.names
validator.metrics.names = validator.names
validator.nc = model.model.model[-1].nc
validator.nm = 32
validator.process = ops.process_mask
validator.plot_masks = []
Prepare calibration and validation datasets#
We can use one dataset as calibration and validation datasets. Name it
quantization_dataset
.
from typing import Dict
import nncf
def transform_fn(data_item: Dict):
input_tensor = validator.preprocess(data_item)["img"].numpy()
return input_tensor
quantization_dataset = nncf.Dataset(data_loader, transform_fn)
INFO:nncf:NNCF initialized successfully. Supported frameworks detected: torch, openvino
Prepare validation function#
from functools import partial
import torch
from nncf.quantization.advanced_parameters import AdvancedAccuracyRestorerParameters
def validation_ac(
compiled_model: ov.CompiledModel,
validation_loader: torch.utils.data.DataLoader,
validator: Validator,
num_samples: int = None,
log=True,
) -> float:
validator.seen = 0
validator.jdict = []
validator.stats = dict(tp_m=[], tp=[], conf=[], pred_cls=[], target_cls=[])
validator.batch_i = 1
validator.confusion_matrix = ConfusionMatrix(nc=validator.nc)
num_outputs = len(compiled_model.outputs)
counter = 0
for batch_i, batch in enumerate(validation_loader):
if num_samples is not None and batch_i == num_samples:
break
batch = validator.preprocess(batch)
results = compiled_model(batch["img"])
if num_outputs == 1:
preds = torch.from_numpy(results[compiled_model.output(0)])
else:
preds = [
torch.from_numpy(results[compiled_model.output(0)]),
torch.from_numpy(results[compiled_model.output(1)]),
]
preds = validator.postprocess(preds)
validator.update_metrics(preds, batch)
counter += 1
stats = validator.get_stats()
if num_outputs == 1:
stats_metrics = stats["metrics/mAP50-95(B)"]
else:
stats_metrics = stats["metrics/mAP50-95(M)"]
if log:
print(f"Validate: dataset length = {counter}, metric value = {stats_metrics:.3f}")
return stats_metrics
validation_fn = partial(validation_ac, validator=validator, log=False)
Run quantization with accuracy control#
You should provide the calibration dataset and the validation dataset. It can be the same dataset.
parameter
max_drop
defines the accuracy drop threshold. The quantization process stops when the degradation of accuracy metric on the validation dataset is less than themax_drop
. The default value is 0.01. NNCF will stop the quantization and report an error if themax_drop
value can’t be reached.drop_type
defines how the accuracy drop will be calculated: ABSOLUTE (used by default) or RELATIVE.ranking_subset_size
- size of a subset that is used to rank layers by their contribution to the accuracy drop. Default value is 300, and the more samples it has the better ranking, potentially. Here we use the value 25 to speed up the execution.NOTE: Execution can take tens of minutes and requires up to 15 GB of free memory
quantized_model = nncf.quantize_with_accuracy_control(
ov_model,
quantization_dataset,
quantization_dataset,
validation_fn=validation_fn,
max_drop=0.01,
preset=nncf.QuantizationPreset.MIXED,
subset_size=128,
advanced_accuracy_restorer_parameters=AdvancedAccuracyRestorerParameters(ranking_subset_size=25),
)
Output()
/home/maleksandr/test_notebooks/ultrali/openvino_notebooks/notebooks/quantizing-model-with-accuracy-control/venv/lib/python3.10/site-packages/nncf/experimental/tensor/tensor.py:84: RuntimeWarning: invalid value encountered in multiply
return Tensor(self.data * unwrap_tensor_data(other))
Output()
INFO:nncf:Validation of initial model was started
INFO:nncf:Elapsed Time: 00:00:00
INFO:nncf:Elapsed Time: 00:00:03
INFO:nncf:Metric of initial model: 0.3651327608484117
INFO:nncf:Collecting values for each data item using the initial model
INFO:nncf:Elapsed Time: 00:00:04
INFO:nncf:Validation of quantized model was started
INFO:nncf:Elapsed Time: 00:00:00
INFO:nncf:Elapsed Time: 00:00:03
INFO:nncf:Metric of quantized model: 0.34040251506886543
INFO:nncf:Collecting values for each data item using the quantized model
INFO:nncf:Elapsed Time: 00:00:04
INFO:nncf:Accuracy drop: 0.024730245779546245 (absolute)
INFO:nncf:Accuracy drop: 0.024730245779546245 (absolute)
INFO:nncf:Total number of quantized operations in the model: 92
INFO:nncf:Number of parallel workers to rank quantized operations: 1
INFO:nncf:ORIGINAL metric is used to rank quantizers
Output()
INFO:nncf:Elapsed Time: 00:01:38
INFO:nncf:Changing the scope of quantizer nodes was started
INFO:nncf:Reverted 1 operations to the floating-point precision:
__module.model.4.m.0.cv2.conv/aten::_convolution/Convolution
INFO:nncf:Accuracy drop with the new quantization scope is 0.023408466397916217 (absolute)
INFO:nncf:Reverted 1 operations to the floating-point precision:
__module.model.18.m.0.cv2.conv/aten::_convolution/Convolution
INFO:nncf:Accuracy drop with the new quantization scope is 0.024749654890442174 (absolute)
INFO:nncf:Re-calculating ranking scores for remaining groups
Output()
INFO:nncf:Elapsed Time: 00:01:36
INFO:nncf:Reverted 1 operations to the floating-point precision:
__module.model.22.proto.cv3.conv/aten::_convolution/Convolution
INFO:nncf:Accuracy drop with the new quantization scope is 0.023229513575966754 (absolute)
INFO:nncf:Reverted 2 operations to the floating-point precision:
__module.model.22/aten::add/Add_6
__module.model.22/aten::sub/Subtract
INFO:nncf:Accuracy drop with the new quantization scope is 0.02425608378963906 (absolute)
INFO:nncf:Re-calculating ranking scores for remaining groups
Output()
INFO:nncf:Elapsed Time: 00:01:35
INFO:nncf:Reverted 1 operations to the floating-point precision:
__module.model.6.m.0.cv2.conv/aten::_convolution/Convolution
INFO:nncf:Accuracy drop with the new quantization scope is 0.023297881500256024 (absolute)
INFO:nncf:Reverted 2 operations to the floating-point precision:
__module.model.12.cv2.conv/aten::_convolution/Convolution
__module.model.12.m.0.cv1.conv/aten::_convolution/Convolution
INFO:nncf:Accuracy drop with the new quantization scope is 0.021779128052922092 (absolute)
INFO:nncf:Reverted 2 operations to the floating-point precision:
__module.model.7.conv/aten::_convolution/Convolution
__module.model.12.cv1.conv/aten::_convolution/Convolution
INFO:nncf:Accuracy drop with the new quantization scope is 0.01696486517685941 (absolute)
INFO:nncf:Reverted 2 operations to the floating-point precision:
__module.model.22/aten::add/Add_7
__module.model.22/aten::sub/Subtract_1
INFO:nncf:Algorithm completed: achieved required accuracy drop 0.005923437521415831 (absolute)
INFO:nncf:9 out of 92 were reverted back to the floating-point precision:
__module.model.4.m.0.cv2.conv/aten::_convolution/Convolution
__module.model.22.proto.cv3.conv/aten::_convolution/Convolution
__module.model.6.m.0.cv2.conv/aten::_convolution/Convolution
__module.model.12.cv2.conv/aten::_convolution/Convolution
__module.model.12.m.0.cv1.conv/aten::_convolution/Convolution
__module.model.7.conv/aten::_convolution/Convolution
__module.model.12.cv1.conv/aten::_convolution/Convolution
__module.model.22/aten::add/Add_7
__module.model.22/aten::sub/Subtract_1
Compare Accuracy and Performance of the Original and Quantized Models#
Now we can compare metrics of the Original non-quantized OpenVINO IR
model and Quantized OpenVINO IR model to make sure that the max_drop
is not exceeded.
device = device_widget()
device
Dropdown(description='Device:', index=4, options=('CPU', 'GPU.0', 'GPU.1', 'GPU.2', 'AUTO'), value='AUTO')
core = ov.Core()
ov_config = {}
if device.value != "CPU":
quantized_model.reshape({0: [1, 3, 640, 640]})
if "GPU" in device.value or ("AUTO" in device.value and "GPU" in core.available_devices):
ov_config = {"GPU_DISABLE_WINOGRAD_CONVOLUTION": "YES"}
quantized_compiled_model = core.compile_model(quantized_model, device.value, ov_config)
compiled_ov_model = core.compile_model(ov_model, device.value, ov_config)
pt_result = validation_ac(compiled_ov_model, data_loader, validator)
quantized_result = validation_ac(quantized_compiled_model, data_loader, validator)
print(f"[Original OpenVINO]: {pt_result:.4f}")
print(f"[Quantized OpenVINO]: {quantized_result:.4f}")
Validate: dataset length = 128, metric value = 0.368
Validate: dataset length = 128, metric value = 0.357
[Original OpenVINO]: 0.3677
[Quantized OpenVINO]: 0.3570
And compare performance.
from pathlib import Path
# Set model directory
MODEL_DIR = Path("model")
MODEL_DIR.mkdir(exist_ok=True)
ir_model_path = MODEL_DIR / "ir_model.xml"
quantized_model_path = MODEL_DIR / "quantized_model.xml"
# Save models to use them in the commandline banchmark app
ov.save_model(ov_model, ir_model_path, compress_to_fp16=False)
ov.save_model(quantized_model, quantized_model_path, compress_to_fp16=False)
# Inference Original model (OpenVINO IR)
! benchmark_app -m $ir_model_path -shape "[1,3,640,640]" -d $device.value -api async
[Step 1/11] Parsing and validating input arguments [ INFO ] Parsing input parameters [Step 2/11] Loading OpenVINO Runtime [ WARNING ] Default duration 120 seconds is used for unknown device AUTO [ INFO ] OpenVINO: [ INFO ] Build ................................. 2024.0.0-14509-34caeefd078-releases/2024/0 [ INFO ] [ INFO ] Device info: [ INFO ] AUTO [ INFO ] Build ................................. 2024.0.0-14509-34caeefd078-releases/2024/0 [ INFO ] [ INFO ] [Step 3/11] Setting device configuration [ WARNING ] Performance hint was not explicitly specified in command line. Device(AUTO) performance hint will be set to PerformanceMode.THROUGHPUT. [Step 4/11] Reading model files [ INFO ] Loading model files [ INFO ] Read model took 13.54 ms [ INFO ] Original model I/O parameters: [ INFO ] Model inputs: [ INFO ] x (node: x) : f32 / [...] / [?,3,?,?] [ INFO ] Model outputs: [ INFO ] *NO_NAME* (node: __module.model.22/aten::cat/Concat_8) : f32 / [...] / [?,116,16..] [ INFO ] input.199 (node: __module.model.22.cv4.2.1.act/aten::silu_/Swish_37) : f32 / [...] / [?,32,8..,8..] [Step 5/11] Resizing model to match image sizes and given batch [ INFO ] Model batch size: 1 [ INFO ] Reshaping model: 'x': [1,3,640,640] [ INFO ] Reshape model took 8.56 ms [Step 6/11] Configuring input of the model [ INFO ] Model inputs: [ INFO ] x (node: x) : u8 / [N,C,H,W] / [1,3,640,640] [ INFO ] Model outputs: [ INFO ] *NO_NAME* (node: __module.model.22/aten::cat/Concat_8) : f32 / [...] / [1,116,8400] [ INFO ] input.199 (node: __module.model.22.cv4.2.1.act/aten::silu_/Swish_37) : f32 / [...] / [1,32,160,160] [Step 7/11] Loading the model to the device [ INFO ] Compile model took 437.16 ms [Step 8/11] Querying optimal runtime parameters [ INFO ] Model: [ INFO ] NETWORK_NAME: Model0 [ INFO ] EXECUTION_DEVICES: ['CPU'] [ INFO ] PERFORMANCE_HINT: PerformanceMode.THROUGHPUT [ INFO ] OPTIMAL_NUMBER_OF_INFER_REQUESTS: 12 [ INFO ] MULTI_DEVICE_PRIORITIES: CPU [ INFO ] CPU: [ INFO ] AFFINITY: Affinity.CORE [ INFO ] CPU_DENORMALS_OPTIMIZATION: False [ INFO ] CPU_SPARSE_WEIGHTS_DECOMPRESSION_RATE: 1.0 [ INFO ] DYNAMIC_QUANTIZATION_GROUP_SIZE: 0 [ INFO ] ENABLE_CPU_PINNING: True [ INFO ] ENABLE_HYPER_THREADING: True [ INFO ] EXECUTION_DEVICES: ['CPU'] [ INFO ] EXECUTION_MODE_HINT: ExecutionMode.PERFORMANCE [ INFO ] INFERENCE_NUM_THREADS: 36 [ INFO ] INFERENCE_PRECISION_HINT: <Type: 'float32'> [ INFO ] KV_CACHE_PRECISION: <Type: 'float16'> [ INFO ] LOG_LEVEL: Level.NO [ INFO ] NETWORK_NAME: Model0 [ INFO ] NUM_STREAMS: 12 [ INFO ] OPTIMAL_NUMBER_OF_INFER_REQUESTS: 12 [ INFO ] PERFORMANCE_HINT: THROUGHPUT [ INFO ] PERFORMANCE_HINT_NUM_REQUESTS: 0 [ INFO ] PERF_COUNT: NO [ INFO ] SCHEDULING_CORE_TYPE: SchedulingCoreType.ANY_CORE [ INFO ] MODEL_PRIORITY: Priority.MEDIUM [ INFO ] LOADED_FROM_CACHE: False [Step 9/11] Creating infer requests and preparing input tensors [ WARNING ] No input files were given for input 'x'!. This input will be filled with random values! [ INFO ] Fill input 'x' with random values [Step 10/11] Measuring performance (Start inference asynchronously, 12 inference requests, limits: 120000 ms duration) [ INFO ] Benchmarking in inference only mode (inputs filling are not included in measurement loop). [ INFO ] First inference took 46.51 ms [Step 11/11] Dumping statistics report [ INFO ] Execution Devices:['CPU'] [ INFO ] Count: 16872 iterations [ INFO ] Duration: 120117.37 ms [ INFO ] Latency: [ INFO ] Median: 85.10 ms [ INFO ] Average: 85.27 ms [ INFO ] Min: 53.55 ms [ INFO ] Max: 108.50 ms [ INFO ] Throughput: 140.46 FPS
# Inference Quantized model (OpenVINO IR)
! benchmark_app -m $quantized_model_path -shape "[1,3,640,640]" -d $device.value -api async
[Step 1/11] Parsing and validating input arguments [ INFO ] Parsing input parameters [Step 2/11] Loading OpenVINO Runtime [ WARNING ] Default duration 120 seconds is used for unknown device AUTO [ INFO ] OpenVINO: [ INFO ] Build ................................. 2024.0.0-14509-34caeefd078-releases/2024/0 [ INFO ] [ INFO ] Device info: [ INFO ] AUTO [ INFO ] Build ................................. 2024.0.0-14509-34caeefd078-releases/2024/0 [ INFO ] [ INFO ] [Step 3/11] Setting device configuration [ WARNING ] Performance hint was not explicitly specified in command line. Device(AUTO) performance hint will be set to PerformanceMode.THROUGHPUT. [Step 4/11] Reading model files [ INFO ] Loading model files [ INFO ] Read model took 20.52 ms [ INFO ] Original model I/O parameters: [ INFO ] Model inputs: [ INFO ] x (node: x) : f32 / [...] / [?,3,?,?] [ INFO ] Model outputs: [ INFO ] *NO_NAME* (node: __module.model.22/aten::cat/Concat_8) : f32 / [...] / [?,116,16..] [ INFO ] input.199 (node: __module.model.22.cv4.2.1.act/aten::silu_/Swish_37) : f32 / [...] / [?,32,8..,8..] [Step 5/11] Resizing model to match image sizes and given batch [ INFO ] Model batch size: 1 [ INFO ] Reshaping model: 'x': [1,3,640,640] [ INFO ] Reshape model took 11.74 ms [Step 6/11] Configuring input of the model [ INFO ] Model inputs: [ INFO ] x (node: x) : u8 / [N,C,H,W] / [1,3,640,640] [ INFO ] Model outputs: [ INFO ] *NO_NAME* (node: __module.model.22/aten::cat/Concat_8) : f32 / [...] / [1,116,8400] [ INFO ] input.199 (node: __module.model.22.cv4.2.1.act/aten::silu_/Swish_37) : f32 / [...] / [1,32,160,160] [Step 7/11] Loading the model to the device [ INFO ] Compile model took 711.53 ms [Step 8/11] Querying optimal runtime parameters [ INFO ] Model: [ INFO ] NETWORK_NAME: Model0 [ INFO ] EXECUTION_DEVICES: ['CPU'] [ INFO ] PERFORMANCE_HINT: PerformanceMode.THROUGHPUT [ INFO ] OPTIMAL_NUMBER_OF_INFER_REQUESTS: 12 [ INFO ] MULTI_DEVICE_PRIORITIES: CPU [ INFO ] CPU: [ INFO ] AFFINITY: Affinity.CORE [ INFO ] CPU_DENORMALS_OPTIMIZATION: False [ INFO ] CPU_SPARSE_WEIGHTS_DECOMPRESSION_RATE: 1.0 [ INFO ] DYNAMIC_QUANTIZATION_GROUP_SIZE: 0 [ INFO ] ENABLE_CPU_PINNING: True [ INFO ] ENABLE_HYPER_THREADING: True [ INFO ] EXECUTION_DEVICES: ['CPU'] [ INFO ] EXECUTION_MODE_HINT: ExecutionMode.PERFORMANCE [ INFO ] INFERENCE_NUM_THREADS: 36 [ INFO ] INFERENCE_PRECISION_HINT: <Type: 'float32'> [ INFO ] KV_CACHE_PRECISION: <Type: 'float16'> [ INFO ] LOG_LEVEL: Level.NO [ INFO ] NETWORK_NAME: Model0 [ INFO ] NUM_STREAMS: 12 [ INFO ] OPTIMAL_NUMBER_OF_INFER_REQUESTS: 12 [ INFO ] PERFORMANCE_HINT: THROUGHPUT [ INFO ] PERFORMANCE_HINT_NUM_REQUESTS: 0 [ INFO ] PERF_COUNT: NO [ INFO ] SCHEDULING_CORE_TYPE: SchedulingCoreType.ANY_CORE [ INFO ] MODEL_PRIORITY: Priority.MEDIUM [ INFO ] LOADED_FROM_CACHE: False [Step 9/11] Creating infer requests and preparing input tensors [ WARNING ] No input files were given for input 'x'!. This input will be filled with random values! [ INFO ] Fill input 'x' with random values [Step 10/11] Measuring performance (Start inference asynchronously, 12 inference requests, limits: 120000 ms duration) [ INFO ] Benchmarking in inference only mode (inputs filling are not included in measurement loop). [ INFO ] First inference took 35.64 ms [Step 11/11] Dumping statistics report [ INFO ] Execution Devices:['CPU'] [ INFO ] Count: 33564 iterations [ INFO ] Duration: 120059.16 ms [ INFO ] Latency: [ INFO ] Median: 42.72 ms [ INFO ] Average: 42.76 ms [ INFO ] Min: 23.29 ms [ INFO ] Max: 67.71 ms [ INFO ] Throughput: 279.56 FPS