Fix DDP issues and Support DDP for all training scripts (#448)

* Fix DDP bugs

* Fix DDP bugs for finetune and db

* refactor model loader

* fix DDP network

* try to fix DDP network in train unet only

* remove unuse DDP import

* refactor DDP transform

* refactor DDP transform

* fix sample images bugs

* change DDP tranform location

* add autocast to train_db

* support DDP in XTI

* Clear DDP import

fine_tune.py

@@ -90,7 +90,7 @@ def train(args):
     weight_dtype, save_dtype = train_util.prepare_dtype(args)
 
     # モデルを読み込む
-    text_encoder, vae, unet, load_stable_diffusion_format = train_util.load_target_model(args, weight_dtype)
+    text_encoder, vae, unet, load_stable_diffusion_format = train_util.load_target_model(args, weight_dtype, accelerator)
 
     # verify load/save model formats
     if load_stable_diffusion_format:
@@ -228,6 +228,9 @@ def train(args):
     else:
         unet, optimizer, train_dataloader, lr_scheduler = accelerator.prepare(unet, optimizer, train_dataloader, lr_scheduler)
 
+    # transform DDP after prepare
+    text_encoder, unet, _ = train_util.transform_DDP(text_encoder, unet)
+
     # 実験的機能：勾配も含めたfp16学習を行う　PyTorchにパッチを当ててfp16でのgrad scaleを有効にする
     if args.full_fp16:
         train_util.patch_accelerator_for_fp16_training(accelerator)

library/train_util.py

@@ -19,6 +19,7 @@ from typing import (
     Union,
 )
 from accelerate import Accelerator
+import gc
 import glob
 import math
 import os
@@ -30,6 +31,7 @@ import toml
 
 from tqdm import tqdm
 import torch
+from torch.nn.parallel import DistributedDataParallel as DDP
 from torch.optim import Optimizer
 from torchvision import transforms
 from transformers import CLIPTokenizer
@@ -2866,7 +2868,7 @@ def prepare_dtype(args: argparse.Namespace):
     return weight_dtype, save_dtype
 
 
-def load_target_model(args: argparse.Namespace, weight_dtype, device="cpu"):
+def _load_target_model(args: argparse.Namespace, weight_dtype, device="cpu"):
     name_or_path = args.pretrained_model_name_or_path
     name_or_path = os.readlink(name_or_path) if os.path.islink(name_or_path) else name_or_path
     load_stable_diffusion_format = os.path.isfile(name_or_path)  # determine SD or Diffusers
@@ -2895,6 +2897,36 @@ def load_target_model(args: argparse.Namespace, weight_dtype, device="cpu"):
     return text_encoder, vae, unet, load_stable_diffusion_format
 
 
+def transform_DDP(text_encoder, unet, network=None):
+    # Transform text_encoder, unet and network from DistributedDataParallel
+    return (encoder.module if type(encoder) == DDP else encoder for encoder in [text_encoder, unet, network])
+
+
+def load_target_model(args, weight_dtype, accelerator):
+    # load models for each process
+    for pi in range(accelerator.state.num_processes):
+        if pi == accelerator.state.local_process_index:
+            print(f"loading model for process {accelerator.state.local_process_index}/{accelerator.state.num_processes}")
+
+            text_encoder, vae, unet, load_stable_diffusion_format = _load_target_model(
+                args, weight_dtype, accelerator.device if args.lowram else "cpu"
+            )
+
+            # work on low-ram device
+            if args.lowram:
+                text_encoder.to(accelerator.device)
+                unet.to(accelerator.device)
+                vae.to(accelerator.device)
+
+            gc.collect()
+            torch.cuda.empty_cache()
+        accelerator.wait_for_everyone()
+
+    text_encoder, unet, _ = transform_DDP(text_encoder, unet, network=None)
+
+    return text_encoder, vae, unet, load_stable_diffusion_format
+
+
 def patch_accelerator_for_fp16_training(accelerator):
     org_unscale_grads = accelerator.scaler._unscale_grads_
 

networks/lora_interrogator.py

@@ -23,7 +23,7 @@ def interrogate(args):
   print(f"loading SD model: {args.sd_model}")
   args.pretrained_model_name_or_path = args.sd_model
   args.vae = None
-  text_encoder, vae, unet, _ = train_util.load_target_model(args,weights_dtype, DEVICE)
+  text_encoder, vae, unet, _ = train_util._load_target_model(args,weights_dtype, DEVICE)
 
   print(f"loading LoRA: {args.model}")
   network, weights_sd = lora.create_network_from_weights(1.0, args.model, vae, text_encoder, unet)

train_db.py

@@ -92,7 +92,7 @@ def train(args):
     weight_dtype, save_dtype = train_util.prepare_dtype(args)
 
     # モデルを読み込む
-    text_encoder, vae, unet, load_stable_diffusion_format = train_util.load_target_model(args, weight_dtype)
+    text_encoder, vae, unet, load_stable_diffusion_format = train_util.load_target_model(args, weight_dtype, accelerator)
 
     # verify load/save model formats
     if load_stable_diffusion_format:
@@ -196,6 +196,9 @@ def train(args):
     else:
         unet, optimizer, train_dataloader, lr_scheduler = accelerator.prepare(unet, optimizer, train_dataloader, lr_scheduler)
 
+    # transform DDP after prepare
+    text_encoder, unet, _ = train_util.transform_DDP(text_encoder, unet)
+
     if not train_text_encoder:
         text_encoder.to(accelerator.device, dtype=weight_dtype)  # to avoid 'cpu' vs 'cuda' error
 
@@ -297,6 +300,7 @@ def train(args):
                 noisy_latents = noise_scheduler.add_noise(latents, noise, timesteps)
 
                 # Predict the noise residual
+                with accelerator.autocast():
                     noise_pred = unet(noisy_latents, timesteps, encoder_hidden_states).sample
 
                 if args.v_parameterization:

train_network.py

@@ -1,4 +1,3 @@
-from torch.nn.parallel import DistributedDataParallel as DDP
 import importlib
 import argparse
 import gc
@@ -144,24 +143,7 @@ def train(args):
     weight_dtype, save_dtype = train_util.prepare_dtype(args)
 
     # モデルを読み込む
-    for pi in range(accelerator.state.num_processes):
-        # TODO: modify other training scripts as well
-        if pi == accelerator.state.local_process_index:
-            print(f"loading model for process {accelerator.state.local_process_index}/{accelerator.state.num_processes}")
-
-            text_encoder, vae, unet, _ = train_util.load_target_model(
-                args, weight_dtype, accelerator.device if args.lowram else "cpu"
-            )
-
-            # work on low-ram device
-            if args.lowram:
-                text_encoder.to(accelerator.device)
-                unet.to(accelerator.device)
-                vae.to(accelerator.device)
-
-            gc.collect()
-            torch.cuda.empty_cache()
-        accelerator.wait_for_everyone()
+    text_encoder, vae, unet, _ = train_util.load_target_model(args, weight_dtype, accelerator)
 
     # モデルに xformers とか memory efficient attention を組み込む
     train_util.replace_unet_modules(unet, args.mem_eff_attn, args.xformers)
@@ -279,6 +261,9 @@ def train(args):
     else:
         network, optimizer, train_dataloader, lr_scheduler = accelerator.prepare(network, optimizer, train_dataloader, lr_scheduler)
 
+    # transform DDP after prepare (train_network here only)
+    text_encoder, unet, network = train_util.transform_DDP(text_encoder, unet, network)
+
     unet.requires_grad_(False)
     unet.to(accelerator.device, dtype=weight_dtype)
     text_encoder.requires_grad_(False)
@@ -288,20 +273,11 @@ def train(args):
         text_encoder.train()
 
         # set top parameter requires_grad = True for gradient checkpointing works
-        if type(text_encoder) == DDP:
-            text_encoder.module.text_model.embeddings.requires_grad_(True)
-        else:
         text_encoder.text_model.embeddings.requires_grad_(True)
     else:
         unet.eval()
         text_encoder.eval()
         
-    # support DistributedDataParallel
-    if type(text_encoder) == DDP:
-        text_encoder = text_encoder.module
-        unet = unet.module
-        network = network.module
-
     network.prepare_grad_etc(text_encoder, unet)
 
     if not cache_latents:

train_textual_inversion.py

@@ -98,7 +98,7 @@ def train(args):
     weight_dtype, save_dtype = train_util.prepare_dtype(args)
 
     # モデルを読み込む
-    text_encoder, vae, unet, _ = train_util.load_target_model(args, weight_dtype)
+    text_encoder, vae, unet, _ = train_util.load_target_model(args, weight_dtype, accelerator)
 
     # Convert the init_word to token_id
     if args.init_word is not None:
@@ -280,6 +280,9 @@ def train(args):
         text_encoder, optimizer, train_dataloader, lr_scheduler
     )
 
+    # transform DDP after prepare
+    text_encoder, unet, _ = train_util.transform_DDP(text_encoder, unet)
+
     index_no_updates = torch.arange(len(tokenizer)) < token_ids[0]
     # print(len(index_no_updates), torch.sum(index_no_updates))
     orig_embeds_params = unwrap_model(text_encoder).get_input_embeddings().weight.data.detach().clone()

train_textual_inversion_XTI.py

@@ -104,7 +104,7 @@ def train(args):
     weight_dtype, save_dtype = train_util.prepare_dtype(args)
 
     # モデルを読み込む
-    text_encoder, vae, unet, _ = train_util.load_target_model(args, weight_dtype)
+    text_encoder, vae, unet, _ = train_util.load_target_model(args, weight_dtype, accelerator)
 
     # Convert the init_word to token_id
     if args.init_word is not None:
@@ -314,6 +314,9 @@ def train(args):
         text_encoder, optimizer, train_dataloader, lr_scheduler
     )
 
+    # transform DDP after prepare
+    text_encoder, unet, _ = train_util.transform_DDP(text_encoder, unet)
+
     index_no_updates = torch.arange(len(tokenizer)) < token_ids_XTI[0]
     # print(len(index_no_updates), torch.sum(index_no_updates))
     orig_embeds_params = unwrap_model(text_encoder).get_input_embeddings().weight.data.detach().clone()