stable_diffusion_pipeline.py

#
# SPDX-FileCopyrightText: Copyright (c) 1993-2024 NVIDIA CORPORATION & AFFILIATES. All rights reserved.
# SPDX-License-Identifier: Apache-2.0
#
# 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.
#

import modelopt.torch.opt as mto
import modelopt.torch.quantization as mtq
from cuda import cudart
from diffusers import (
    DDIMScheduler,
    DDPMScheduler,
    EulerDiscreteScheduler,
    EulerAncestralDiscreteScheduler,
    LCMScheduler, LMSDiscreteScheduler,
    PNDMScheduler,
    UniPCMultistepScheduler,
    DDPMWuerstchenScheduler
)
from hashlib import md5
import inspect
from models import (
    get_clip_embedding_dim,
    get_path,
    LoraLoader,
    make_tokenizer,
    CLIPModel,
    CLIPWithProjModel,
    UNetModel,
    UNetXLModel,
    VAEModel,
    VAEEncoderModel,
    make_scheduler
)
import numpy as np
import nvtx
import json
import os
import pathlib
import tensorrt as trt
import time
import torch
from typing import Optional, List
from utilities import (
    PIPELINE_TYPE,
    TRT_LOGGER,
    Engine,
    get_refit_weights,
    load_calib_prompts,
    merge_loras,
    prepare_mask_and_masked_image,
    save_image,
    unload_model
)
from utils_modelopt import (
    filter_func,
    quantize_lvl,
    get_int8_config,
    check_lora,
    set_fmha,
    generate_fp8_scales,
    SD_FP8_FP16_DEFAULT_CONFIG,
    SD_FP8_FP32_DEFAULT_CONFIG,
)

class StableDiffusionPipeline:
    SCHEDULER_DEFAULTS = {
        "1.4": "PNDM",
        "1.5": "PNDM",
        "dreamshaper-7": "PNDM",
        "2.0-base": "DDIM",
        "2.0": "DDIM",
        "2.1-base": "PNDM",
        "2.1": "DDIM",
        "xl-1.0" : "Euler",
        "xl-turbo": "EulerA",
        "svd-xt-1.1": "Euler",
        "cascade": "DDPMWuerstchen"
    }
    """
    Application showcasing the acceleration of Stable Diffusion pipelines using NVidia TensorRT.
    """
    def __init__(
        self,
        version='1.5',
        pipeline_type=PIPELINE_TYPE.TXT2IMG,
        max_batch_size=16,
        denoising_steps=30,
        scheduler=None,
        guidance_scale=7.5,
        device='cuda',
        output_dir='.',
        hf_token=None,
        verbose=False,
        nvtx_profile=False,
        use_cuda_graph=False,
        vae_scaling_factor=0.18215,
        framework_model_dir='pytorch_model',
        controlnets=None,
        lora_scale: Optional[List[int]] = None,
        lora_path: Optional[List[str]] = None,
        return_latents=False,
        torch_inference='',
    ):
        """
        Initializes the Diffusion pipeline.

        Args:
            version (str):
                The version of the pipeline. Should be one of [1.4, 1.5, 2.0, 2.0-base, 2.1, 2.1-base]
            pipeline_type (PIPELINE_TYPE):
                Type of current pipeline.
            max_batch_size (int):
                Maximum batch size for dynamic batch engine.
            denoising_steps (int):
                The number of denoising steps.
                More denoising steps usually lead to a higher quality image at the expense of slower inference.
            scheduler (str):
                The scheduler to guide the denoising process. Must be one of [DDIM, DPM, EulerA, Euler, LCM, LMSD, PNDM].
            guidance_scale (float):
                Guidance scale is enabled by setting as > 1.
                Higher guidance scale encourages to generate images that are closely linked to the text prompt, usually at the expense of lower image quality.
            device (str):
                PyTorch device to run inference. Default: 'cuda'
            output_dir (str):
                Output directory for log files and image artifacts
            hf_token (str):
                HuggingFace User Access Token to use for downloading Stable Diffusion model checkpoints.
            verbose (bool):
                Enable verbose logging.
            nvtx_profile (bool):
                Insert NVTX profiling markers.
            use_cuda_graph (bool):
                Use CUDA graph to capture engine execution and then launch inference
            vae_scaling_factor (float):
                VAE scaling factor
            framework_model_dir (str):
                cache directory for framework checkpoints
            controlnets (str):
                Which ControlNet/ControlNets to use.
            return_latents (bool):
                Skip decoding the image and return latents instead.
            torch_inference (str):
                Run inference with PyTorch (using specified compilation mode) instead of TensorRT.
        """

        self.denoising_steps = denoising_steps
        self.guidance_scale = guidance_scale
        self.do_classifier_free_guidance = (guidance_scale > 1.0)
        self.vae_scaling_factor = vae_scaling_factor

        self.max_batch_size = max_batch_size

        self.framework_model_dir = framework_model_dir
        self.output_dir = output_dir
        for directory in [self.framework_model_dir, self.output_dir]:
            if not os.path.exists(directory):
                print(f"[I] Create directory: {directory}")
                pathlib.Path(directory).mkdir(parents=True)

        self.hf_token = hf_token
        self.device = device
        self.verbose = verbose
        self.nvtx_profile = nvtx_profile

        self.version = version
        self.controlnets = controlnets

        # Pipeline type
        self.pipeline_type = pipeline_type
        if self.pipeline_type.is_txt2img() or self.pipeline_type.is_controlnet():
            self.stages = ['clip','unet','vae']
        elif self.pipeline_type.is_img2img() or self.pipeline_type.is_inpaint():
            self.stages = ['vae_encoder', 'clip','unet','vae']
        elif self.pipeline_type.is_sd_xl_base():
            self.stages = ['clip', 'clip2', 'unetxl']
            if not return_latents:
                self.stages.append('vae')
        elif self.pipeline_type.is_sd_xl_refiner():
            self.stages = ['clip2', 'unetxl', 'vae']
        elif self.pipeline_type.is_img2vid():
            self.stages = ['clip-vis', 'clip-imgfe', 'unet-temp', 'vae-temp']
        elif self.pipeline_type.is_cascade_prior():
            self.stages = ['clip', 'unet']
        elif self.pipeline_type.is_cascade_decoder():
            self.stages = ['clip', 'unet', 'vqgan']
        else:
            raise ValueError(f"Unsupported pipeline {self.pipeline_type.name}.")
        self.return_latents = return_latents

        if not scheduler:
            scheduler = 'UniPC' if self.pipeline_type.is_controlnet() else self.SCHEDULER_DEFAULTS.get(version, 'DDIM')
            print(f"[I] Autoselected scheduler: {scheduler}")

        scheduler_class_map = {
            "DDIM" : DDIMScheduler,
            "DDPM" : DDPMScheduler,
            "EulerA" : EulerAncestralDiscreteScheduler,
            "Euler" : EulerDiscreteScheduler,
            "LCM" : LCMScheduler,
            "LMSD" : LMSDiscreteScheduler,
            "PNDM" : PNDMScheduler,
            "UniPC" : UniPCMultistepScheduler,
            "DDPMWuerstchen" : DDPMWuerstchenScheduler,
        }
        try:
            scheduler_class = scheduler_class_map[scheduler]
        except KeyError:
            raise ValueError(f"Unsupported scheduler {scheduler}.  Should be one of {list(scheduler_class.keys())}.")
        self.scheduler = make_scheduler(scheduler_class, version, pipeline_type, hf_token, framework_model_dir)

        self.config = {}
        if self.pipeline_type.is_sd_xl():
            self.config['clip_hidden_states'] = True
        self.torch_inference = torch_inference
        if self.torch_inference:
            torch._inductor.config.conv_1x1_as_mm = True
            torch._inductor.config.coordinate_descent_tuning = True
            torch._inductor.config.epilogue_fusion = False
            torch._inductor.config.coordinate_descent_check_all_directions = True
        self.use_cuda_graph = use_cuda_graph

        # initialized in loadEngines()
        self.models = {}
        self.torch_models = {}
        self.engine = {}
        self.shared_device_memory = None

        # initialize lora loader and scales
        self.lora_loader = None
        self.lora_scales = dict()
        if lora_path:
            self.lora_loader = LoraLoader(lora_path)
            assert len(lora_path) == len(lora_scale)
            for i, path in enumerate(lora_path):
                self.lora_scales[path] = lora_scale[i]

        # initialized in loadResources()
        self.events = {}
        self.generator = None
        self.markers = {}
        self.seed = None
        self.stream = None
        self.tokenizer = None

    def loadResources(self, image_height, image_width, batch_size, seed):
        # Initialize noise generator
        if seed:
            self.seed = seed
            self.generator = torch.Generator(device="cuda").manual_seed(seed)

        # Create CUDA events and stream
        for stage in ['clip', 'denoise', 'vae', 'vae_encoder', 'vqgan']:
            self.events[stage] = [cudart.cudaEventCreate()[1], cudart.cudaEventCreate()[1]]
        self.stream = cudart.cudaStreamCreate()[1]

        # Allocate TensorRT I/O buffers
        if not self.torch_inference:
            for model_name, obj in self.models.items():
                self.engine[model_name].allocate_buffers(shape_dict=obj.get_shape_dict(batch_size, image_height, image_width), device=self.device)

    def teardown(self):
        for e in self.events.values():
            cudart.cudaEventDestroy(e[0])
            cudart.cudaEventDestroy(e[1])

        for engine in self.engine.values():
            del engine

        if self.shared_device_memory:
            cudart.cudaFree(self.shared_device_memory)

        for torch_model in self.torch_models.values():
            del torch_model

        cudart.cudaStreamDestroy(self.stream)
        del self.stream

    def cachedModelName(self, model_name):
        if self.pipeline_type.is_inpaint():
            model_name += '_inpaint'
        return model_name

    def getOnnxPath(self, model_name, onnx_dir, opt=True, suffix=''):
        onnx_model_dir = os.path.join(onnx_dir, self.cachedModelName(model_name)+suffix+('.opt' if opt else ''))
        os.makedirs(onnx_model_dir, exist_ok=True)
        return os.path.join(onnx_model_dir, 'model.onnx')

    def getEnginePath(self, model_name, engine_dir, enable_refit=False, suffix=''):
        return os.path.join(engine_dir, self.cachedModelName(model_name)+suffix+('.refit' if enable_refit else '')+'.trt'+trt.__version__+'.plan')

    def getWeightsMapPath(self, model_name, onnx_dir):
        onnx_model_dir = os.path.join(onnx_dir, self.cachedModelName(model_name)+'.opt')
        os.makedirs(onnx_model_dir, exist_ok=True)
        return os.path.join(onnx_model_dir, 'weights_map.json')

    def getRefitNodesPath(self, model_name, onnx_dir, suffix=''):
        onnx_model_dir = os.path.join(onnx_dir, self.cachedModelName(model_name)+'.opt')
        os.makedirs(onnx_model_dir, exist_ok=True)
        return os.path.join(onnx_model_dir, 'refit'+suffix+'.json')

    def getStateDictPath(self, model_name, onnx_dir, suffix=''):
        onnx_model_dir = os.path.join(onnx_dir, self.cachedModelName(model_name)+suffix)
        os.makedirs(onnx_model_dir, exist_ok=True)
        return os.path.join(onnx_model_dir, 'state_dict.pt')

    def initializeModels(self, framework_model_dir, int8, fp8):
        # Load text tokenizer(s)
        if not self.pipeline_type.is_sd_xl_refiner():
            self.tokenizer = make_tokenizer(self.version, self.pipeline_type, self.hf_token, framework_model_dir)
        if self.pipeline_type.is_sd_xl():
            self.tokenizer2 = make_tokenizer(self.version, self.pipeline_type, self.hf_token, framework_model_dir, subfolder='tokenizer_2')

        # Load pipeline models
        models_args = {'version': self.version, 'pipeline': self.pipeline_type, 'device': self.device,
            'hf_token': self.hf_token, 'verbose': self.verbose, 'framework_model_dir': framework_model_dir,
            'max_batch_size': self.max_batch_size}

        if 'clip' in self.stages:
            subfolder = 'text_encoder'
            self.models['clip'] = CLIPModel(**models_args, fp16=True, embedding_dim=get_clip_embedding_dim(self.version, self.pipeline_type), output_hidden_states=self.config.get('clip_hidden_states', False), subfolder=subfolder)

        if 'clip2' in self.stages:
            subfolder = 'text_encoder_2'
            self.models['clip2'] = CLIPWithProjModel(**models_args, fp16=True, output_hidden_states=self.config.get('clip_hidden_states', False), subfolder=subfolder)

        lora_dict, lora_alphas = (None, None)
        if 'unet' in self.stages:
            if self.lora_loader:
                lora_dict, lora_alphas = self.lora_loader.get_dicts('unet')
                assert len(lora_dict) == len(self.lora_scales)
            self.models['unet'] = UNetModel(**models_args, fp16=True, int8=int8, fp8=fp8, controlnets=self.controlnets,
                lora_scales=self.lora_scales, lora_dict=lora_dict, lora_alphas=lora_alphas, do_classifier_free_guidance=self.do_classifier_free_guidance)

        if 'unetxl' in self.stages:
            if not self.pipeline_type.is_sd_xl_refiner() and self.lora_loader:
                lora_dict, lora_alphas = self.lora_loader.get_dicts('unet')
                assert len(lora_dict) == len(self.lora_scales)
            self.models['unetxl'] = UNetXLModel(**models_args, fp16=True, int8=int8, fp8=fp8,
                lora_scales=self.lora_scales, lora_dict=lora_dict, lora_alphas=lora_alphas, do_classifier_free_guidance=self.do_classifier_free_guidance)

        vae_fp16 = not self.pipeline_type.is_sd_xl()

        if 'vae' in self.stages:
            self.models['vae'] = VAEModel(**models_args, fp16=vae_fp16)

        if 'vae_encoder' in self.stages:
            self.models['vae_encoder'] = VAEEncoderModel(**models_args, fp16=vae_fp16)

    def loadEngines(
        self,
        engine_dir,
        framework_model_dir,
        onnx_dir,
        onnx_opset,
        opt_batch_size,
        opt_image_height,
        opt_image_width,
        optimization_level=3,
        static_batch=False,
        static_shape=True,
        enable_refit=False,
        enable_all_tactics=False,
        timing_cache=None,
        int8=False,
        fp8=False,
        quantization_level=2.5,
        quantization_percentile=1.0,
        quantization_alpha=0.8,
        calibration_size=32,
        calib_batch_size=2,
    ):
        """
        Build and load engines for TensorRT accelerated inference.
        Export ONNX models first, if applicable.

        Args:
            engine_dir (str):
                Directory to store the TensorRT engines.
            framework_model_dir (str):
                Directory to store the framework model ckpt.
            onnx_dir (str):
                Directory to store the ONNX models.
            onnx_opset (int):
                ONNX opset version to export the models.
            opt_batch_size (int):
                Batch size to optimize for during engine building.
            opt_image_height (int):
                Image height to optimize for during engine building. Must be a multiple of 8.
            opt_image_width (int):
                Image width to optimize for during engine building. Must be a multiple of 8.
            optimization_level (int):
                Optimization level to build the TensorRT engine with.
            static_batch (bool):
                Build engine only for specified opt_batch_size.
            static_shape (bool):
                Build engine only for specified opt_image_height & opt_image_width. Default = True.
            enable_refit (bool):
                Build engines with refit option enabled.
            enable_all_tactics (bool):
                Enable all tactic sources during TensorRT engine builds.
            timing_cache (str):
                Path to the timing cache to speed up TensorRT build.
            int8 (bool):
                Whether to quantize to int8 format or not (SDXL, SD15 and SD21 only).
            fp8 (bool):
                Whether to quantize to fp8 format or not (SDXL, SD15 and SD21 only).
            quantization_level (float):
                Controls which layers to quantize. 1: CNN, 2: CNN+FFN, 2.5: CNN+FFN+QKV, 3: CNN+FC
            quantization_percentile (float):
                Control quantization scaling factors (amax) collecting range, where the minimum amax in
                range(n_steps * percentile) will be collected. Recommendation: 1.0
            quantization_alpha (float):
                The alpha parameter for SmoothQuant quantization used for linear layers.
                Recommendation: 0.8 for SDXL
            calibration_size (int):
                The number of steps to use for calibrating the model for quantization.
                Recommendation: 32, 64, 128 for SDXL
            calib_batch_size (int):
                The batch size to use for calibration. Defaults to 2.
        """
        # Create directories if missing
        for directory in [engine_dir, onnx_dir]:
            if not os.path.exists(directory):
                print(f"[I] Create directory: {directory}")
                pathlib.Path(directory).mkdir(parents=True)

        # Initialize models
        self.initializeModels(framework_model_dir, int8, fp8)

        # Configure pipeline models to load
        model_names = self.models.keys()
        lora_suffix = '-'+'-'.join([str(md5(path.encode('utf-8')).hexdigest())+'-'+('%.2f' % self.lora_scales[path]) for path in sorted(self.lora_loader.paths)]) if self.lora_loader else ''
        # Enable refit and LoRA merging only for UNet & UNetXL for now
        do_engine_refit = dict(zip(model_names, [not self.pipeline_type.is_sd_xl_refiner() and enable_refit and model_name.startswith('unet') for model_name in model_names]))
        do_lora_merge = dict(zip(model_names, [not enable_refit and self.lora_loader and model_name.startswith('unet') for model_name in model_names]))
        # Torch fallback for VAE if specified
        torch_fallback = dict(zip(model_names, [self.torch_inference for model_name in model_names]))
        model_suffix = dict(zip(model_names, [lora_suffix if do_lora_merge[model_name] else '' for model_name in model_names]))
        use_int8 = dict.fromkeys(model_names, False)
        use_fp8 = dict.fromkeys(model_names, False)
        if int8:
            assert self.pipeline_type.is_sd_xl_base() or self.version in ["1.4", "1.5", "2.1", "2.1-base"], "int8 quantization only supported for SDXL, SD1.4, SD1.5 and SD2.1 pipeline"
            model_name = 'unetxl' if self.pipeline_type.is_sd_xl() else 'unet'
            use_int8[model_name] = True
            model_suffix[model_name] += f"-int8.l{quantization_level}.bs2.s{self.denoising_steps}.c{calibration_size}.p{quantization_percentile}.a{quantization_alpha}"
        elif fp8:
            assert self.pipeline_type.is_sd_xl() or self.version in ["1.4", "1.5", "2.1", "2.1-base"], "fp8 quantization only supported for SDXL, SD1.4, SD1.5 and SD2.1 pipeline"
            model_name = 'unetxl' if self.pipeline_type.is_sd_xl() else 'unet'
            use_fp8[model_name] = True
            model_suffix[model_name] += f"-fp8.l{quantization_level}.bs2.s{self.denoising_steps}.c{calibration_size}.p{quantization_percentile}.a{quantization_alpha}"
        onnx_path = dict(zip(model_names, [self.getOnnxPath(model_name, onnx_dir, opt=False, suffix=model_suffix[model_name]) for model_name in model_names]))
        onnx_opt_path = dict(zip(model_names, [self.getOnnxPath(model_name, onnx_dir, suffix=model_suffix[model_name]) for model_name in model_names]))
        engine_path = dict(zip(model_names, [self.getEnginePath(model_name, engine_dir, do_engine_refit[model_name], suffix=model_suffix[model_name]) for model_name in model_names]))
        weights_map_path = dict(zip(model_names, [(self.getWeightsMapPath(model_name, onnx_dir) if do_engine_refit[model_name] else None) for model_name in model_names]))

        for model_name, obj in self.models.items():
            if torch_fallback[model_name]:
                continue
            # Export models to ONNX and save weights name mapping
            do_export_onnx = not os.path.exists(engine_path[model_name]) and not os.path.exists(onnx_opt_path[model_name])
            do_export_weights_map = weights_map_path[model_name] and not os.path.exists(weights_map_path[model_name])
            if do_export_onnx or do_export_weights_map:
                # Non-quantized ONNX export
                if not use_int8[model_name] and not use_fp8[model_name]:
                    obj.export_onnx(onnx_path[model_name], onnx_opt_path[model_name], onnx_opset, opt_image_height, opt_image_width, enable_lora_merge=do_lora_merge[model_name], static_shape=static_shape)
                else:
                    pipeline = obj.get_pipeline()
                    model = pipeline.unet
                    if use_fp8[model_name] and quantization_level == 4.0:
                        set_fmha(model)

                    state_dict_path = self.getStateDictPath(model_name, onnx_dir, suffix=model_suffix[model_name])
                    if not os.path.exists(state_dict_path):
                        print(f"[I] Calibrated weights not found, generating {state_dict_path}")
                        calibration_file = os.path.join(os.path.dirname(os.path.realpath(__file__)), 'calibration-prompts.txt')
                        calibration_prompts = load_calib_prompts(calib_batch_size, calibration_file)
                        # TODO check size > calibration_size
                        def do_calibrate(pipeline, calibration_prompts, **kwargs):
                            for i_th, prompts in enumerate(calibration_prompts):
                                if i_th >= kwargs["calib_size"]:
                                    return
                                pipeline(
                                    prompt=prompts,
                                    num_inference_steps=kwargs["n_steps"],
                                    negative_prompt=[
                                        "normal quality, low quality, worst quality, low res, blurry, nsfw, nude"
                                    ]
                                    * len(prompts),
                                ).images

                        def forward_loop(model):
                            pipeline.unet = model
                            do_calibrate(
                                pipeline=pipeline,
                                calibration_prompts=calibration_prompts,
                                calib_size=calibration_size // calib_batch_size,
                                n_steps=self.denoising_steps,
                            )

                        print(f"[I] Performing calibration for {calibration_size} steps.")
                        if use_int8[model_name]:
                            quant_config = get_int8_config(
                                model,
                                quantization_level,
                                quantization_alpha,
                                quantization_percentile,
                                self.denoising_steps
                            )
                        elif use_fp8[model_name]:
                            quant_config = SD_FP8_FP32_DEFAULT_CONFIG if self.version == "2.1" else SD_FP8_FP16_DEFAULT_CONFIG
                        check_lora(model)
                        mtq.quantize(model, quant_config, forward_loop)
                        mto.save(model, state_dict_path)
                    else:
                        mto.restore(model, state_dict_path)

                    print(f"[I] Generating quantized ONNX model: {onnx_opt_path[model_name]}")
                    if not os.path.exists(onnx_path[model_name]):
                        quantize_lvl(model, quantization_level)
                        mtq.disable_quantizer(model, filter_func)
                        if use_fp8[model_name]:
                            generate_fp8_scales(model)
                    else:
                        model = None
                    obj.export_onnx(onnx_path[model_name], onnx_opt_path[model_name], onnx_opset, opt_image_height, opt_image_width, custom_model=model, static_shape=static_shape)

            # FIXME do_export_weights_map needs ONNX graph
            if do_export_weights_map:
                print(f"[I] Saving weights map: {weights_map_path[model_name]}")
                obj.export_weights_map(onnx_opt_path[model_name], weights_map_path[model_name])

        # Build TensorRT engines
        for model_name, obj in self.models.items():
            if torch_fallback[model_name]:
                continue
            engine = Engine(engine_path[model_name])
            if not os.path.exists(engine_path[model_name]):
                update_output_names = obj.get_output_names() + obj.extra_output_names if obj.extra_output_names else None
                fp16amp = obj.fp16 if not use_fp8[model_name] else False
                bf16amp = obj.bf16 if not use_fp8[model_name] else False
                strongly_typed = False if not use_fp8[model_name] else True
                extra_build_args = {'verbose': self.verbose}
                extra_build_args['builder_optimization_level'] = optimization_level
                if use_int8[model_name]:
                    extra_build_args['int8'] = True
                    extra_build_args['precision_constraints'] = 'prefer'
                engine.build(onnx_opt_path[model_name],
                    strongly_typed=strongly_typed,
                    fp16=fp16amp,
                    bf16=bf16amp,
                    input_profile=obj.get_input_profile(
                        opt_batch_size, opt_image_height, opt_image_width,
                        static_batch=static_batch, static_shape=static_shape
                    ),
                    enable_refit=do_engine_refit[model_name],
                    enable_all_tactics=enable_all_tactics,
                    timing_cache=timing_cache,
                    update_output_names=update_output_names,
                    **extra_build_args)
            self.engine[model_name] = engine

        # Load TensorRT engines
        for model_name, obj in self.models.items():
            if torch_fallback[model_name]:
                continue
            self.engine[model_name].load()
            if do_engine_refit[model_name] and obj.lora_dict:
                assert weights_map_path[model_name]
                with open(weights_map_path[model_name], 'r') as fp_wts:
                    print(f"[I] Loading weights map: {weights_map_path[model_name]} ")
                    [weights_name_mapping, weights_shape_mapping] = json.load(fp_wts)
                    refit_weights_path = self.getRefitNodesPath(model_name, engine_dir, suffix=lora_suffix)
                    if not os.path.exists(refit_weights_path):
                            print(f"[I] Saving refit weights: {refit_weights_path}")
                            model = merge_loras(obj.get_model(), obj.lora_dict, obj.lora_alphas, obj.lora_scales)
                            refit_weights = get_refit_weights(model.state_dict(), onnx_opt_path[model_name], weights_name_mapping, weights_shape_mapping)
                            torch.save(refit_weights, refit_weights_path)
                            unload_model(model)
                    else:
                        print(f"[I] Loading refit weights: {refit_weights_path}")
                        refit_weights = torch.load(refit_weights_path)
                    self.engine[model_name].refit(refit_weights, obj.fp16)

        # Load torch models
        for model_name, obj in self.models.items():
            if torch_fallback[model_name]:
                self.torch_models[model_name] = obj.get_model(torch_inference=self.torch_inference)

    def calculateMaxDeviceMemory(self):
        max_device_memory = 0
        for model_name, engine in self.engine.items():
            max_device_memory = max(max_device_memory, engine.engine.device_memory_size)
        return max_device_memory

    def activateEngines(self, shared_device_memory=None):
        if shared_device_memory is None:
            max_device_memory = self.calculateMaxDeviceMemory()
            _, shared_device_memory = cudart.cudaMalloc(max_device_memory)
        self.shared_device_memory = shared_device_memory
        # Load and activate TensorRT engines
        for engine in self.engine.values():
            engine.activate(device_memory=self.shared_device_memory)

    def runEngine(self, model_name, feed_dict):
        engine = self.engine[model_name]
        return engine.infer(feed_dict, self.stream, use_cuda_graph=self.use_cuda_graph)

    def initialize_latents(self, batch_size, unet_channels, latent_height, latent_width, latents_dtype=torch.float32):
        latents_dtype = latents_dtype # text_embeddings.dtype
        latents_shape = (batch_size, unet_channels, latent_height, latent_width)
        latents = torch.randn(latents_shape, device=self.device, dtype=latents_dtype, generator=self.generator)
        # Scale the initial noise by the standard deviation required by the scheduler
        latents = latents * self.scheduler.init_noise_sigma
        return latents

    def profile_start(self, name, color='blue'):
        if self.nvtx_profile:
            self.markers[name] = nvtx.start_range(message=name, color=color)
        if name in self.events:
            cudart.cudaEventRecord(self.events[name][0], 0)

    def profile_stop(self, name):
        if name in self.events:
            cudart.cudaEventRecord(self.events[name][1], 0)
        if self.nvtx_profile:
            nvtx.end_range(self.markers[name])

    def preprocess_images(self, batch_size, images=()):
        if not images:
            return ()
        self.profile_start('preprocess', color='pink')
        input_images=[]
        for image in images:
            image = image.to(self.device).float()
            if image.shape[0] != batch_size:
                image = image.repeat(batch_size, 1, 1, 1)
            input_images.append(image)
        self.profile_stop('preprocess')
        return tuple(input_images)

    def preprocess_controlnet_images(self, batch_size, images=None):
        '''
        images: List of PIL.Image.Image
        '''
        if images is None:
            return None
        self.profile_start('preprocess', color='pink')
        images = [(np.array(i.convert("RGB")).astype(np.float32) / 255.0)[..., None].transpose(3, 2, 0, 1).repeat(batch_size, axis=0) for i in images]
        # do_classifier_free_guidance
        images = [torch.cat([torch.from_numpy(i).to(self.device).float()] * 2) for i in images]
        images = torch.cat([image[None, ...] for image in images], dim=0)
        self.profile_stop('preprocess')
        return images

    def encode_prompt(self, prompt, negative_prompt, encoder='clip', pooled_outputs=False, output_hidden_states=False):
        self.profile_start('clip', color='green')

        tokenizer = self.tokenizer2 if encoder == 'clip2' else self.tokenizer

        def tokenize(prompt, output_hidden_states):
            text_input_ids = tokenizer(
                prompt,
                padding="max_length",
                max_length=tokenizer.model_max_length,
                truncation=True,
                return_tensors="pt",
            ).input_ids.type(torch.int32).to(self.device)

            text_hidden_states = None
            if self.torch_inference:
                outputs = self.torch_models[encoder](text_input_ids, output_hidden_states=output_hidden_states)
                text_embeddings = outputs[0].clone()
                if output_hidden_states:
                    text_hidden_states = outputs['hidden_states'][-2].clone()
            else:
                # NOTE: output tensor for CLIP must be cloned because it will be overwritten when called again for negative prompt
                outputs = self.runEngine(encoder, {'input_ids': text_input_ids})
                text_embeddings = outputs['text_embeddings'].clone()
                if output_hidden_states:
                    text_hidden_states = outputs['hidden_states'].clone()
            return text_embeddings, text_hidden_states

        # Tokenize prompt
        text_embeddings, text_hidden_states = tokenize(prompt, output_hidden_states)

        if self.do_classifier_free_guidance:
            # Tokenize negative prompt
            uncond_embeddings, uncond_hidden_states = tokenize(negative_prompt, output_hidden_states)

            # Concatenate the unconditional and text embeddings into a single batch to avoid doing two forward passes for classifier free guidance
            text_embeddings = torch.cat([uncond_embeddings, text_embeddings]).to(dtype=torch.float16)

        if pooled_outputs:
            pooled_output = text_embeddings

        if output_hidden_states:
            text_embeddings = torch.cat([uncond_hidden_states, text_hidden_states]).to(dtype=torch.float16) if self.do_classifier_free_guidance else text_hidden_states

        self.profile_stop('clip')
        if pooled_outputs:
            return text_embeddings, pooled_output
        return text_embeddings

    # from diffusers (get_timesteps)
    def get_timesteps(self, num_inference_steps, strength, denoising_start=None):
        # get the original timestep using init_timestep
        if denoising_start is None:
            init_timestep = min(int(num_inference_steps * strength), num_inference_steps)
            t_start = max(num_inference_steps - init_timestep, 0)
        else:
            t_start = 0

        timesteps = self.scheduler.timesteps[t_start * self.scheduler.order :]

        # Strength is irrelevant if we directly request a timestep to start at;
        # that is, strength is determined by the denoising_start instead.
        if denoising_start is not None:
            discrete_timestep_cutoff = int(
                round(
                    self.scheduler.config.num_train_timesteps
                    - (denoising_start * self.scheduler.config.num_train_timesteps)
                )
            )

            num_inference_steps = (timesteps < discrete_timestep_cutoff).sum().item()
            if self.scheduler.order == 2 and num_inference_steps % 2 == 0:
                # if the scheduler is a 2nd order scheduler we might have to do +1
                # because `num_inference_steps` might be even given that every timestep
                # (except the highest one) is duplicated. If `num_inference_steps` is even it would
                # mean that we cut the timesteps in the middle of the denoising step
                # (between 1st and 2nd devirative) which leads to incorrect results. By adding 1
                # we ensure that the denoising process always ends after the 2nd derivate step of the scheduler
                num_inference_steps = num_inference_steps + 1

            # because t_n+1 >= t_n, we slice the timesteps starting from the end
            timesteps = timesteps[-num_inference_steps:]
            return timesteps, num_inference_steps

        return timesteps, num_inference_steps - t_start

    def denoise_latent(self,
        latents,
        text_embeddings,
        denoiser='unet',
        timesteps=None,
        step_offset=0,
        mask=None,
        masked_image_latents=None,
        image_guidance=1.5,
        controlnet_imgs=None,
        controlnet_scales=None,
        text_embeds=None,
        time_ids=None):

        assert image_guidance > 1.0, "Image guidance has to be > 1.0"

        controlnet_imgs = self.preprocess_controlnet_images(latents.shape[0], controlnet_imgs)

        do_autocast = self.torch_inference != '' and self.models[denoiser].fp16
        with torch.autocast('cuda', enabled=do_autocast):
            self.profile_start('denoise', color='blue')
            for step_index, timestep in enumerate(timesteps):
                # Expand the latents if we are doing classifier free guidance
                latent_model_input = torch.cat([latents] * 2) if self.do_classifier_free_guidance else latents
                latent_model_input = self.scheduler.scale_model_input(latent_model_input, timestep)
                if isinstance(mask, torch.Tensor):
                    latent_model_input = torch.cat([latent_model_input, mask, masked_image_latents], dim=1)

                # Predict the noise residual
                if self.torch_inference:
                    params = {"sample": latent_model_input, "timestep": timestep, "encoder_hidden_states": text_embeddings}
                    if controlnet_imgs is not None:
                        params.update({"images": controlnet_imgs, "controlnet_scales": controlnet_scales})
                    added_cond_kwargs = {}
                    if text_embeds != None:
                        added_cond_kwargs.update({'text_embeds': text_embeds})
                    if time_ids != None:
                        added_cond_kwargs.update({'time_ids': time_ids})
                    if text_embeds != None or time_ids != None:
                        params.update({'added_cond_kwargs': added_cond_kwargs})
                    noise_pred = self.torch_models[denoiser](**params)["sample"]
                else:
                    timestep_float = timestep.float() if timestep.dtype != torch.float32 else timestep

                    params = {"sample": latent_model_input, "timestep": timestep_float, "encoder_hidden_states": text_embeddings}
                    if controlnet_imgs is not None:
                        params.update({"images": controlnet_imgs, "controlnet_scales": controlnet_scales})
                    if text_embeds != None:
                        params.update({'text_embeds': text_embeds})
                    if time_ids != None:
                        params.update({'time_ids': time_ids})
                    noise_pred = self.runEngine(denoiser, params)['latent']

                # Perform guidance
                if self.do_classifier_free_guidance:
                    noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
                    noise_pred = noise_pred_uncond + self.guidance_scale * (noise_pred_text - noise_pred_uncond)

                # from diffusers (prepare_extra_step_kwargs)
                extra_step_kwargs = {}
                if "eta" in set(inspect.signature(self.scheduler.step).parameters.keys()):
                    # TODO: configurable eta
                    eta = 0.0
                    extra_step_kwargs["eta"] = eta
                if "generator" in set(inspect.signature(self.scheduler.step).parameters.keys()):
                    extra_step_kwargs["generator"] = self.generator

                latents = self.scheduler.step(noise_pred, timestep, latents, **extra_step_kwargs, return_dict=False)[0]

            latents = 1. / self.vae_scaling_factor * latents
            latents = latents.to(dtype=torch.float32)

        self.profile_stop('denoise')
        return latents

    def encode_image(self, input_image):
        self.profile_start('vae_encoder', color='red')
        if self.torch_inference:
            image_latents = self.torch_models['vae_encoder'](input_image)
        else:
            image_latents = self.runEngine('vae_encoder', {'images': input_image})['latent']
        image_latents = self.vae_scaling_factor * image_latents
        self.profile_stop('vae_encoder')
        return image_latents

    def decode_latent(self, latents):
        self.profile_start('vae', color='red')
        if self.torch_inference:
            images = self.torch_models['vae'](latents, return_dict=False)[0]
        else:
            images = self.runEngine('vae', {'latent': latents})['images']
        self.profile_stop('vae')
        return images

    def print_summary(self, denoising_steps, walltime_ms, batch_size):
        print('|-----------------|--------------|')
        print('| {:^15} | {:^12} |'.format('Module', 'Latency'))
        print('|-----------------|--------------|')
        if 'vae_encoder' in self.stages:
            print('| {:^15} | {:>9.2f} ms |'.format('VAE-Enc', cudart.cudaEventElapsedTime(self.events['vae_encoder'][0], self.events['vae_encoder'][1])[1]))
        print('| {:^15} | {:>9.2f} ms |'.format('CLIP', cudart.cudaEventElapsedTime(self.events['clip'][0], self.events['clip'][1])[1]))
        print('| {:^15} | {:>9.2f} ms |'.format('UNet'+('+CNet' if self.pipeline_type.is_controlnet() else '')+' x '+str(denoising_steps), cudart.cudaEventElapsedTime(self.events['denoise'][0], self.events['denoise'][1])[1]))
        print('| {:^15} | {:>9.2f} ms |'.format('VAE-Dec', cudart.cudaEventElapsedTime(self.events['vae'][0], self.events['vae'][1])[1]))
        print('|-----------------|--------------|')
        print('| {:^15} | {:>9.2f} ms |'.format('Pipeline', walltime_ms))
        print('|-----------------|--------------|')
        print('Throughput: {:.2f} image/s'.format(batch_size*1000./walltime_ms))

    def save_image(self, images, pipeline, prompt, seed):
        # Save image
        image_name_prefix = pipeline+''.join(set(['-'+prompt[i].replace(' ','_')[:10] for i in range(len(prompt))]))+'-'+str(seed)+'-'
        image_name_suffix = 'torch' if self.torch_inference else 'trt'
        save_image(images, self.output_dir, image_name_prefix, image_name_suffix)

    def infer(
        self,
        prompt,
        negative_prompt,
        image_height,
        image_width,
        input_image=None,
        image_strength=0.75,
        mask_image=None,
        controlnet_scales=None,
        aesthetic_score=6.0,
        negative_aesthetic_score=2.5,
        warmup=False,
        verbose=False,
        save_image=True,
    ):
        """
        Run the diffusion pipeline.

        Args:
            prompt (str):
                The text prompt to guide image generation.
            negative_prompt (str):
                The prompt not to guide the image generation.
            image_height (int):
                Height (in pixels) of the image to be generated. Must be a multiple of 8.
            image_width (int):
                Width (in pixels) of the image to be generated. Must be a multiple of 8.
            input_image (image):
                Input image used to initialize the latents or to be inpainted.
            image_strength (float):
                Strength of transformation applied to input_image. Must be between 0 and 1.
            mask_image (image):
                Mask image containg the region to be inpainted.
            controlnet_scales (torch.Tensor)
                A tensor which containes ControlNet scales, essential for multi ControlNet.
                Must be equal to number of Controlnets.
            warmup (bool):
                Indicate if this is a warmup run.
            verbose (bool):
                Verbose in logging
            save_image (bool):
                Save the generated image (if applicable)
        """
        assert len(prompt) == len(negative_prompt)
        batch_size = len(prompt)

        # Spatial dimensions of latent tensor
        latent_height = image_height // 8
        latent_width = image_width // 8

        if self.generator and self.seed:
            self.generator.manual_seed(self.seed)

        num_inference_steps = self.denoising_steps

        with torch.inference_mode(), trt.Runtime(TRT_LOGGER):
            torch.cuda.synchronize()
            e2e_tic = time.perf_counter()

            # TODO: support custom timesteps
            timesteps = None
            if timesteps is not None:
                if not ("timesteps" in set(inspect.signature(self.scheduler.set_timesteps).parameters.keys())):
                    raise ValueError(
                        f"The current scheduler class {self.scheduler.__class__}'s `set_timesteps` does not support custom"
                        f" timestep schedules. Please check whether you are using the correct scheduler."
                    )
                self.scheduler.set_timesteps(timesteps=timesteps, device=self.device)
                assert self.denoising_steps == len(self.scheduler.timesteps)
            else:
                self.scheduler.set_timesteps(self.denoising_steps, device=self.device)
            timesteps = self.scheduler.timesteps.to(self.device)

            denoise_kwargs = {}
            if not (self.pipeline_type.is_img2img() or self.pipeline_type.is_sd_xl_refiner()):
                # Initialize latents
                latents = self.initialize_latents(batch_size=batch_size,
                    unet_channels=4,
                    latent_height=latent_height,
                    latent_width=latent_width)
            if self.pipeline_type.is_controlnet():
                denoise_kwargs.update({'controlnet_imgs': input_image, 'controlnet_scales': controlnet_scales})

            # Pre-process and VAE encode input image
            if self.pipeline_type.is_img2img() or self.pipeline_type.is_inpaint() or self.pipeline_type.is_sd_xl_refiner():
                assert input_image != None
                # Initialize timesteps and pre-process input image
                timesteps, num_inference_steps = self.get_timesteps(self.denoising_steps, image_strength)
            denoise_kwargs.update({'timesteps': timesteps})
            if self.pipeline_type.is_img2img() or self.pipeline_type.is_sd_xl_refiner():
                latent_timestep = timesteps[:1].repeat(batch_size)
                input_image = self.preprocess_images(batch_size, (input_image,))[0]
                # Encode if not a latent
                image_latents = input_image if input_image.shape[1] == 4 else self.encode_image(input_image)
                # Add noise to latents using timesteps
                noise = torch.randn(image_latents.shape, generator=self.generator, device=self.device, dtype=torch.float32)
                latents = self.scheduler.add_noise(image_latents, noise, latent_timestep)
            elif self.pipeline_type.is_inpaint():
                mask, mask_image = self.preprocess_images(batch_size, prepare_mask_and_masked_image(input_image, mask_image))
                mask = torch.nn.functional.interpolate(mask, size=(latent_height, latent_width))
                mask = torch.cat([mask] * 2)
                masked_image_latents = self.encode_image(mask_image)
                masked_image_latents = torch.cat([masked_image_latents] * 2)
                denoise_kwargs.update({'mask': mask, 'masked_image_latents': masked_image_latents})

            # CLIP text encoder(s)
            if self.pipeline_type.is_sd_xl():
                text_embeddings2, pooled_embeddings2 = self.encode_prompt(prompt, negative_prompt,
                        encoder='clip2', pooled_outputs=True, output_hidden_states=True)

                # Merge text embeddings
                if self.pipeline_type.is_sd_xl_base():
                    text_embeddings = self.encode_prompt(prompt, negative_prompt, output_hidden_states=True)
                    text_embeddings = torch.cat([text_embeddings, text_embeddings2], dim=-1)
                else:
                    text_embeddings = text_embeddings2

                # Time embeddings
                def _get_add_time_ids(original_size, crops_coords_top_left, target_size, dtype, aesthetic_score=None, negative_aesthetic_score=None):
                    if self.pipeline_type.is_sd_xl_refiner(): #self.requires_aesthetics_score:
                        add_time_ids = list(original_size + crops_coords_top_left + (aesthetic_score,))
                        if self.do_classifier_free_guidance:
                            add_neg_time_ids = list(original_size + crops_coords_top_left + (negative_aesthetic_score,))
                    else:
                        add_time_ids = list(original_size + crops_coords_top_left + target_size)
                        if self.do_classifier_free_guidance:
                            add_neg_time_ids = list(original_size + crops_coords_top_left + target_size)
                    add_time_ids = torch.tensor([add_time_ids], dtype=dtype, device=self.device)
                    if self.do_classifier_free_guidance:
                        add_neg_time_ids = torch.tensor([add_neg_time_ids], dtype=dtype, device=self.device)
                        add_time_ids = torch.cat([add_neg_time_ids, add_time_ids], dim=0)
                    return add_time_ids

                original_size = (image_height, image_width)
                crops_coords_top_left = (0, 0)
                target_size = (image_height, image_width)
                if self.pipeline_type.is_sd_xl_refiner():
                    add_time_ids = _get_add_time_ids(
                        original_size, crops_coords_top_left, target_size, dtype=text_embeddings.dtype, aesthetic_score=aesthetic_score, negative_aesthetic_score=negative_aesthetic_score
                    )
                else:
                    add_time_ids = _get_add_time_ids(
                        original_size, crops_coords_top_left, target_size, dtype=text_embeddings.dtype
                    )
                add_time_ids = add_time_ids.repeat(batch_size, 1)
                denoise_kwargs.update({'text_embeds': pooled_embeddings2, 'time_ids': add_time_ids})
            else:
                text_embeddings = self.encode_prompt(prompt, negative_prompt)

            # UNet denoiser + (optional) ControlNet(s)
            denoiser = 'unetxl' if self.pipeline_type.is_sd_xl() else 'unet'
            latents = self.denoise_latent(latents, text_embeddings, denoiser=denoiser, **denoise_kwargs)

            # VAE decode latent (if applicable)
            if self.return_latents:
                latents = latents * self.vae_scaling_factor
            else:
                images = self.decode_latent(latents)

            torch.cuda.synchronize()
            e2e_toc = time.perf_counter()

        walltime_ms = (e2e_toc - e2e_tic) * 1000.
        if not warmup:
            self.print_summary(num_inference_steps, walltime_ms, batch_size)
            if not self.return_latents and save_image:
                # post-process images
                images = ((images + 1) * 255 / 2).clamp(0, 255).detach().permute(0, 2, 3, 1).round().type(torch.uint8).cpu().numpy()
                self.save_image(images, self.pipeline_type.name.lower(), prompt, self.seed)

        return (latents, walltime_ms) if self.return_latents else (images, walltime_ms)

    def run(self, prompt, negative_prompt, height, width, batch_size, batch_count, num_warmup_runs, use_cuda_graph, **kwargs):
        # Process prompt
        if not isinstance(prompt, list):
            raise ValueError(f"`prompt` must be of type `str` list, but is {type(prompt)}")
        prompt = prompt * batch_size

        if not isinstance(negative_prompt, list):
            raise ValueError(f"`--negative-prompt` must be of type `str` list, but is {type(negative_prompt)}")
        if len(negative_prompt) == 1:
            negative_prompt = negative_prompt * batch_size

        num_warmup_runs = max(1, num_warmup_runs) if use_cuda_graph else num_warmup_runs
        if num_warmup_runs > 0:
            print("[I] Warming up ..")
            for _ in range(num_warmup_runs):
                self.infer(prompt, negative_prompt, height, width, warmup=True, **kwargs)

        for _ in range(batch_count):
            print("[I] Running StableDiffusion pipeline")
            if self.nvtx_profile:
                cudart.cudaProfilerStart()
            self.infer(prompt, negative_prompt, height, width, warmup=False, **kwargs)
            if self.nvtx_profile:
                cudart.cudaProfilerStop()