553 lines
21 KiB
Python
553 lines
21 KiB
Python
# SPDX-License-Identifier: Apache-2.0
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import json
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import math
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import os
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import time
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from typing import Any
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import torch
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import torch.distributed as dist
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import torch.distributed.checkpoint as dcp
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from einops import rearrange
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from safetensors.torch import save_file
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from fastvideo.v1.distributed.parallel_state import (get_sp_parallel_rank,
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get_sp_world_size)
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from fastvideo.v1.logger import init_logger
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from fastvideo.v1.training.checkpointing_utils import (ModelWrapper,
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OptimizerWrapper,
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RandomStateWrapper,
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SchedulerWrapper)
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logger = init_logger(__name__)
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_HAS_ERRORED_CLIP_GRAD_NORM_WHILE_HANDLING_FAILING_DTENSOR_CASES = False
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def gather_state_dict_on_cpu_rank0(
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model,
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device: torch.device | None = None,
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) -> dict[str, Any]:
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rank = dist.get_rank()
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cpu_state_dict = {}
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sharded_sd = model.state_dict()
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for param_name, param in sharded_sd.items():
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if hasattr(param, "_local_tensor"):
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# DTensor case
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if param.is_cpu:
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# Gather directly on CPU
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param = param.full_tensor()
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else:
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if device is not None:
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param = param.to(device)
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param = param.full_tensor()
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else:
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# Regular tensor case
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if param.is_cpu:
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pass
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else:
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if device is not None:
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param = param.to(device)
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if rank == 0:
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cpu_state_dict[param_name] = param.cpu()
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return cpu_state_dict
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def compute_density_for_timestep_sampling(
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weighting_scheme: str,
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batch_size: int,
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generator,
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logit_mean: float | None = None,
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logit_std: float | None = None,
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mode_scale: float | None = None,
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):
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"""
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Compute the density for sampling the timesteps when doing SD3 training.
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Courtesy: This was contributed by Rafie Walker in https://github.com/huggingface/diffusers/pull/8528.
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SD3 paper reference: https://arxiv.org/abs/2403.03206v1.
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"""
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if weighting_scheme == "logit_normal":
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# See 3.1 in the SD3 paper ($rf/lognorm(0.00,1.00)$).
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u = torch.normal(
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mean=logit_mean,
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std=logit_std,
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size=(batch_size, ),
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device="cpu",
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generator=generator,
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)
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u = torch.nn.functional.sigmoid(u)
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elif weighting_scheme == "mode":
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u = torch.rand(size=(batch_size, ), device="cpu", generator=generator)
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u = 1 - u - mode_scale * (torch.cos(math.pi * u / 2)**2 - 1 + u)
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else:
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u = torch.rand(size=(batch_size, ), device="cpu", generator=generator)
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return u
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def get_sigmas(noise_scheduler,
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device,
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timesteps,
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n_dim=4,
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dtype=torch.float32) -> torch.Tensor:
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sigmas = noise_scheduler.sigmas.to(device=device, dtype=dtype)
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schedule_timesteps = noise_scheduler.timesteps.to(device)
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timesteps = timesteps.to(device)
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step_indices = [(schedule_timesteps == t).nonzero().item()
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for t in timesteps]
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sigma = sigmas[step_indices].flatten()
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while len(sigma.shape) < n_dim:
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sigma = sigma.unsqueeze(-1)
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return sigma
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def save_checkpoint(transformer,
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rank,
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output_dir,
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step,
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optimizer=None,
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dataloader=None,
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scheduler=None,
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noise_generator=None) -> None:
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"""
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Save checkpoint following finetrainer's distributed checkpoint approach.
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Saves both distributed checkpoint and consolidated model weights.
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"""
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save_dir = os.path.join(output_dir, f"checkpoint-{step}")
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os.makedirs(save_dir, exist_ok=True)
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states = {
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"model": ModelWrapper(transformer),
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"random_state": RandomStateWrapper(noise_generator),
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}
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if optimizer is not None:
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states["optimizer"] = OptimizerWrapper(transformer, optimizer)
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if dataloader is not None:
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states["dataloader"] = dataloader
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if scheduler is not None:
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states["scheduler"] = SchedulerWrapper(scheduler)
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dcp_dir = os.path.join(save_dir, "distributed_checkpoint")
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logger.info("rank: %s, saving distributed checkpoint to %s",
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rank,
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dcp_dir,
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local_main_process_only=False)
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begin_time = time.perf_counter()
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dcp.save(states, checkpoint_id=dcp_dir)
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end_time = time.perf_counter()
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logger.info("rank: %s, distributed checkpoint saved in %.2f seconds",
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rank,
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end_time - begin_time,
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local_main_process_only=False)
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cpu_state = gather_state_dict_on_cpu_rank0(transformer, device=None)
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if rank == 0:
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# Save model weights (consolidated)
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transformer_save_dir = os.path.join(save_dir, "transformer")
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os.makedirs(transformer_save_dir, exist_ok=True)
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weight_path = os.path.join(transformer_save_dir,
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"diffusion_pytorch_model.safetensors")
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logger.info("rank: %s, saving consolidated checkpoint to %s",
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rank,
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weight_path,
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local_main_process_only=False)
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# Convert fastvideo custom format to diffusers format and save
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diffusers_state_dict = convert_custom_format_to_diffusers_format(
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cpu_state, transformer)
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save_file(diffusers_state_dict, weight_path)
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logger.info("rank: %s, consolidated checkpoint saved to %s",
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rank,
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weight_path,
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local_main_process_only=False)
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# Save model config
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config_dict = transformer.hf_config
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if "dtype" in config_dict:
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del config_dict["dtype"] # TODO
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config_path = os.path.join(transformer_save_dir, "config.json")
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# save dict as json
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with open(config_path, "w") as f:
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json.dump(config_dict, f, indent=4)
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logger.info("--> checkpoint saved at step %s to %s", step, weight_path)
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def load_checkpoint(transformer,
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rank,
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checkpoint_path,
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optimizer=None,
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dataloader=None,
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scheduler=None,
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noise_generator=None) -> int:
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"""
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Load checkpoint following finetrainer's distributed checkpoint approach.
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Returns the step number from which training should resume.
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"""
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if not os.path.exists(checkpoint_path):
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logger.warning("Checkpoint path %s does not exist", checkpoint_path)
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return 0
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# Extract step number from checkpoint path
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step = int(os.path.basename(checkpoint_path).split('-')[-1])
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if rank == 0:
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logger.info("Loading checkpoint from step %s", step)
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dcp_dir = os.path.join(checkpoint_path, "distributed_checkpoint")
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if not os.path.exists(dcp_dir):
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logger.warning("Distributed checkpoint directory %s does not exist",
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dcp_dir)
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return 0
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states = {
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"model": ModelWrapper(transformer),
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"random_state": RandomStateWrapper(noise_generator),
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}
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if optimizer is not None:
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states["optimizer"] = OptimizerWrapper(transformer, optimizer)
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if dataloader is not None:
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states["dataloader"] = dataloader
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if scheduler is not None:
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states["scheduler"] = SchedulerWrapper(scheduler)
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logger.info("rank: %s, loading distributed checkpoint from %s",
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rank,
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dcp_dir,
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local_main_process_only=False)
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begin_time = time.perf_counter()
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dcp.load(states, checkpoint_id=dcp_dir)
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end_time = time.perf_counter()
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logger.info("rank: %s, distributed checkpoint loaded in %.2f seconds",
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rank,
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end_time - begin_time,
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local_main_process_only=False)
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logger.info("--> checkpoint loaded from step %s", step)
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return step
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def normalize_dit_input(model_type, latents, args=None) -> torch.Tensor:
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if model_type == "hunyuan_hf" or model_type == "hunyuan":
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return latents * 0.476986
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elif model_type == "wan":
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from fastvideo.v1.configs.models.vaes.wanvae import WanVAEConfig
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vae_config = WanVAEConfig()
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latents_mean = torch.tensor(vae_config.arch_config.latents_mean)
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latents_std = 1.0 / torch.tensor(vae_config.arch_config.latents_std)
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latents_mean = latents_mean.view(1, -1, 1, 1,
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1).to(device=latents.device)
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latents_std = latents_std.view(1, -1, 1, 1, 1).to(device=latents.device)
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latents = ((latents.float() - latents_mean) * latents_std).to(latents)
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return latents
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else:
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raise NotImplementedError(f"model_type {model_type} not supported")
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def shard_latents_across_sp(latents: torch.Tensor,
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num_latent_t: int) -> torch.Tensor:
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sp_world_size = get_sp_world_size()
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rank_in_sp_group = get_sp_parallel_rank()
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latents = latents[:, :, :num_latent_t]
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if sp_world_size > 1:
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latents = rearrange(latents,
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"b c (n s) h w -> b c n s h w",
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n=sp_world_size).contiguous()
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latents = latents[:, :, rank_in_sp_group, :, :, :]
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return latents
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def clip_grad_norm_while_handling_failing_dtensor_cases(
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parameters: torch.Tensor | list[torch.Tensor],
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max_norm: float,
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norm_type: float = 2.0,
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error_if_nonfinite: bool = False,
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foreach: bool | None = None,
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pp_mesh: torch.distributed.device_mesh.DeviceMesh | None = None,
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) -> torch.Tensor | None:
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global _HAS_ERRORED_CLIP_GRAD_NORM_WHILE_HANDLING_FAILING_DTENSOR_CASES
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if not _HAS_ERRORED_CLIP_GRAD_NORM_WHILE_HANDLING_FAILING_DTENSOR_CASES:
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try:
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return clip_grad_norm_(parameters, max_norm, norm_type,
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error_if_nonfinite, foreach, pp_mesh)
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except NotImplementedError as e:
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if "DTensor does not support cross-mesh operation" in str(e):
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# https://github.com/pytorch/pytorch/issues/134212
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logger.warning(
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"DTensor does not support cross-mesh operation. If you haven't fully tensor-parallelized your "
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"model, while combining other parallelisms such as FSDP, it could be the reason for this error. "
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"Gradient clipping will be skipped and gradient norm will not be logged."
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)
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except Exception as e:
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logger.warning(
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"An error occurred while clipping gradients: %s. Gradient clipping will be skipped and gradient "
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"norm will not be logged.", e)
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_HAS_ERRORED_CLIP_GRAD_NORM_WHILE_HANDLING_FAILING_DTENSOR_CASES = True
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return None
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# Copied from https://github.com/pytorch/torchtitan/blob/4a169701555ab9bd6ca3769f9650ae3386b84c6e/torchtitan/utils.py#L362
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@torch.no_grad()
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def clip_grad_norm_(
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parameters: torch.Tensor | list[torch.Tensor],
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max_norm: float,
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norm_type: float = 2.0,
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error_if_nonfinite: bool = False,
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foreach: bool | None = None,
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pp_mesh: torch.distributed.device_mesh.DeviceMesh | None = None,
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) -> torch.Tensor:
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r"""
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Clip the gradient norm of parameters.
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Gradient norm clipping requires computing the gradient norm over the entire model.
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`torch.nn.utils.clip_grad_norm_` only computes gradient norm along DP/FSDP/TP dimensions.
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We need to manually reduce the gradient norm across PP stages.
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See https://github.com/pytorch/torchtitan/issues/596 for details.
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Args:
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parameters (`torch.Tensor` or `List[torch.Tensor]`):
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Tensors that will have gradients normalized.
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max_norm (`float`):
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Maximum norm of the gradients after clipping.
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norm_type (`float`, defaults to `2.0`):
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Type of p-norm to use. Can be `inf` for infinity norm.
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error_if_nonfinite (`bool`, defaults to `False`):
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If `True`, an error is thrown if the total norm of the gradients from `parameters` is `nan`, `inf`, or `-inf`.
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foreach (`bool`, defaults to `None`):
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Use the faster foreach-based implementation. If `None`, use the foreach implementation for CUDA and CPU native tensors
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and silently fall back to the slow implementation for other device types.
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pp_mesh (`torch.distributed.device_mesh.DeviceMesh`, defaults to `None`):
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Pipeline parallel device mesh. If not `None`, will reduce gradient norm across PP stages.
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Returns:
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`torch.Tensor`:
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Total norm of the gradients
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"""
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grads = [p.grad for p in parameters if p.grad is not None]
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# TODO(aryan): Wait for next Pytorch release to use `torch.nn.utils.get_total_norm`
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# total_norm = torch.nn.utils.get_total_norm(grads, norm_type, error_if_nonfinite, foreach)
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total_norm = _get_total_norm(grads, norm_type, error_if_nonfinite, foreach)
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# If total_norm is a DTensor, the placements must be `torch.distributed._tensor.ops.math_ops._NormPartial`.
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# We can simply reduce the DTensor to get the total norm in this tensor's process group
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# and then convert it to a local tensor.
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# It has two purposes:
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# 1. to make sure the total norm is computed correctly when PP is used (see below)
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# 2. to return a reduced total_norm tensor whose .item() would return the correct value
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if isinstance(total_norm, torch.distributed.tensor.DTensor):
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# Will reach here if any non-PP parallelism is used.
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# If only using PP, total_norm will be a local tensor.
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total_norm = total_norm.full_tensor()
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if pp_mesh is not None:
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raise NotImplementedError("Pipeline parallel is not supported")
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if math.isinf(norm_type):
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dist.all_reduce(total_norm,
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op=dist.ReduceOp.MAX,
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group=pp_mesh.get_group())
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else:
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total_norm **= norm_type
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dist.all_reduce(total_norm,
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op=dist.ReduceOp.SUM,
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group=pp_mesh.get_group())
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total_norm **= 1.0 / norm_type
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_clip_grads_with_norm_(parameters, max_norm, total_norm, foreach)
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return total_norm
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@torch.no_grad()
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def _clip_grads_with_norm_(
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parameters: torch.Tensor | list[torch.Tensor],
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max_norm: float,
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total_norm: torch.Tensor,
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foreach: bool | None = None,
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) -> None:
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if isinstance(parameters, torch.Tensor):
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parameters = [parameters]
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grads = [p.grad for p in parameters if p.grad is not None]
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max_norm = float(max_norm)
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if len(grads) == 0:
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return
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grouped_grads: dict[tuple[torch.device, torch.dtype],
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tuple[list[list[torch.Tensor]],
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list[int]]] = (_group_tensors_by_device_and_dtype(
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[grads])) # type: ignore[assignment]
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clip_coef = max_norm / (total_norm + 1e-6)
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# Note: multiplying by the clamped coef is redundant when the coef is clamped to 1, but doing so
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# avoids a `if clip_coef < 1:` conditional which can require a CPU <=> device synchronization
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# when the gradients do not reside in CPU memory.
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clip_coef_clamped = torch.clamp(clip_coef, max=1.0)
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for (device, _), ([device_grads], _) in grouped_grads.items():
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if (foreach is None and _has_foreach_support(device_grads, device)) or (
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foreach and _device_has_foreach_support(device)):
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torch._foreach_mul_(device_grads, clip_coef_clamped.to(device))
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elif foreach:
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raise RuntimeError(
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f"foreach=True was passed, but can't use the foreach API on {device.type} tensors"
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)
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else:
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clip_coef_clamped_device = clip_coef_clamped.to(device)
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for g in device_grads:
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g.mul_(clip_coef_clamped_device)
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def _get_total_norm(
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tensors: torch.Tensor | list[torch.Tensor],
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norm_type: float = 2.0,
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error_if_nonfinite: bool = False,
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foreach: bool | None = None,
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) -> torch.Tensor:
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tensors = [tensors] if isinstance(tensors, torch.Tensor) else list(tensors)
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norm_type = float(norm_type)
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if len(tensors) == 0:
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return torch.tensor(0.0)
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first_device = tensors[0].device
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grouped_tensors: dict[tuple[torch.device, torch.dtype],
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tuple[list[list[torch.Tensor]], list[int]]] = (
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_group_tensors_by_device_and_dtype(
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[tensors] # type: ignore[list-item]
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)) # type: ignore[assignment]
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norms: list[torch.Tensor] = []
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for (device, _), ([device_tensors], _) in grouped_tensors.items():
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local_tensors = [
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t.to_local()
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if isinstance(t, torch.distributed.tensor.DTensor) else t
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for t in device_tensors
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]
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if (foreach is None and _has_foreach_support(local_tensors, device)
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) or (foreach and _device_has_foreach_support(device)):
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norms.extend(torch._foreach_norm(local_tensors, norm_type))
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elif foreach:
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raise RuntimeError(
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f"foreach=True was passed, but can't use the foreach API on {device.type} tensors"
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)
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else:
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norms.extend(
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[torch.linalg.vector_norm(g, norm_type) for g in local_tensors])
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total_norm = torch.linalg.vector_norm(
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torch.stack([norm.to(first_device) for norm in norms]), norm_type)
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if error_if_nonfinite and torch.logical_or(total_norm.isnan(),
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total_norm.isinf()):
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raise RuntimeError(
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f"The total norm of order {norm_type} for gradients from "
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"`parameters` is non-finite, so it cannot be clipped. To disable "
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"this error and scale the gradients by the non-finite norm anyway, "
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"set `error_if_nonfinite=False`")
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return total_norm
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def _get_foreach_kernels_supported_devices() -> list[str]:
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r"""Return the device type list that supports foreach kernels."""
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return ["cuda", "xpu", torch._C._get_privateuse1_backend_name()]
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@torch.no_grad()
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def _group_tensors_by_device_and_dtype(
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tensorlistlist: list[list[torch.Tensor | None]],
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|
with_indices: bool = False,
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|
) -> dict[tuple[torch.device, torch.dtype], tuple[
|
|
list[list[torch.Tensor | None]], list[int]]]:
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|
return torch._C._group_tensors_by_device_and_dtype( # type: ignore[no-any-return]
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|
tensorlistlist, with_indices)
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|
|
|
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|
def _device_has_foreach_support(device: torch.device) -> bool:
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|
return device.type in (_get_foreach_kernels_supported_devices() +
|
|
["cpu"]) and not torch.jit.is_scripting()
|
|
|
|
|
|
def _has_foreach_support(tensors: list[torch.Tensor],
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|
device: torch.device) -> bool:
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|
return _device_has_foreach_support(device) and all(
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|
t is None or type(t) in [torch.Tensor] for t in tensors)
|
|
|
|
|
|
def convert_custom_format_to_diffusers_format(state_dict: dict[str, Any],
|
|
transformer) -> dict[str, Any]:
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|
"""
|
|
Convert fastvideo custom format state dict to diffusers format using reverse_param_names_mapping.
|
|
|
|
Args:
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|
state_dict: State dict in training format
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|
transformer: Transformer model object with _reverse_param_names_mapping
|
|
|
|
Returns:
|
|
State dict in diffusers format
|
|
"""
|
|
new_state_dict = {}
|
|
|
|
# Get the reverse mapping from the transformer
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|
reverse_param_names_mapping = transformer._reverse_param_names_mapping
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|
assert reverse_param_names_mapping != {}, "reverse_param_names_mapping is empty"
|
|
|
|
# Group parameters that need to be split (merged parameters)
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|
merge_groups: dict[str, list[tuple[str, int, int]]] = {}
|
|
|
|
# First pass: collect all merge groups
|
|
for training_key, (
|
|
diffusers_key, merge_index,
|
|
num_params_to_merge) in reverse_param_names_mapping.items():
|
|
if merge_index is not None:
|
|
# This is a merged parameter that needs to be split
|
|
if training_key not in merge_groups:
|
|
merge_groups[training_key] = []
|
|
merge_groups[training_key].append(
|
|
(diffusers_key, merge_index, num_params_to_merge))
|
|
|
|
# Second pass: handle merged parameters by splitting them
|
|
used_keys = set()
|
|
for training_key, splits in merge_groups.items():
|
|
if training_key in state_dict:
|
|
v = state_dict[training_key]
|
|
# Sort by merge_index to ensure correct order
|
|
splits.sort(key=lambda x: x[1])
|
|
total = splits[0][2]
|
|
split_size = v.shape[0] // total
|
|
split_tensors = torch.split(v, split_size, dim=0)
|
|
|
|
for diffusers_key, split_index, _ in splits:
|
|
new_state_dict[diffusers_key] = split_tensors[split_index]
|
|
used_keys.add(training_key)
|
|
|
|
# Third pass: handle regular parameters (direct mappings)
|
|
for training_key, v in state_dict.items():
|
|
if training_key in used_keys:
|
|
continue
|
|
|
|
if training_key in reverse_param_names_mapping:
|
|
diffusers_key, merge_index, _ = reverse_param_names_mapping[
|
|
training_key]
|
|
if merge_index is None:
|
|
# Direct mapping
|
|
new_state_dict[diffusers_key] = v
|
|
else:
|
|
# No mapping found, keep as is
|
|
new_state_dict[training_key] = v
|
|
|
|
return new_state_dict
|