import argparse import os from pathlib import Path import torch import torch.distributed as dist import torch.nn as nn import torchvision import torchvision.transforms as transforms from torch.optim import Optimizer from torch.optim.lr_scheduler import MultiStepLR from torch.utils.data import DataLoader from tqdm import tqdm import colossalai from colossalai.accelerator import get_accelerator from colossalai.booster import Booster from colossalai.booster.plugin import GeminiPlugin, LowLevelZeroPlugin, TorchDDPPlugin from colossalai.booster.plugin.dp_plugin_base import DPPluginBase from colossalai.cluster import DistCoordinator from colossalai.nn.optimizer import HybridAdam # ============================== # Prepare Hyperparameters # ============================== NUM_EPOCHS = 80 LEARNING_RATE = 1e-3 def build_dataloader(batch_size: int, coordinator: DistCoordinator, plugin: DPPluginBase): # transform transform_train = transforms.Compose( [transforms.Pad(4), transforms.RandomHorizontalFlip(), transforms.RandomCrop(32), transforms.ToTensor()] ) transform_test = transforms.ToTensor() # CIFAR-10 dataset data_path = os.environ.get("DATA", "./data") with coordinator.priority_execution(): train_dataset = torchvision.datasets.CIFAR10( root=data_path, train=True, transform=transform_train, download=True ) test_dataset = torchvision.datasets.CIFAR10( root=data_path, train=False, transform=transform_test, download=True ) # Data loader train_dataloader = plugin.prepare_dataloader(train_dataset, batch_size=batch_size, shuffle=True, drop_last=True) test_dataloader = plugin.prepare_dataloader(test_dataset, batch_size=batch_size, shuffle=False, drop_last=False) return train_dataloader, test_dataloader @torch.no_grad() def evaluate(model: nn.Module, test_dataloader: DataLoader, coordinator: DistCoordinator) -> float: model.eval() correct = torch.zeros(1, dtype=torch.int64, device=get_accelerator().get_current_device()) total = torch.zeros(1, dtype=torch.int64, device=get_accelerator().get_current_device()) for images, labels in test_dataloader: images = images.cuda() labels = labels.cuda() outputs = model(images) _, predicted = torch.max(outputs.data, 1) total += labels.size(0) correct += (predicted == labels).sum().item() dist.all_reduce(correct) dist.all_reduce(total) accuracy = correct.item() / total.item() if coordinator.is_master(): print(f"Accuracy of the model on the test images: {accuracy * 100:.2f} %") return accuracy def train_epoch( epoch: int, model: nn.Module, optimizer: Optimizer, criterion: nn.Module, train_dataloader: DataLoader, booster: Booster, coordinator: DistCoordinator, ): model.train() with tqdm(train_dataloader, desc=f"Epoch [{epoch + 1}/{NUM_EPOCHS}]", disable=not coordinator.is_master()) as pbar: for images, labels in pbar: images = images.cuda() labels = labels.cuda() # Forward pass outputs = model(images) loss = criterion(outputs, labels) # Backward and optimize booster.backward(loss, optimizer) optimizer.step() optimizer.zero_grad() # Print log info pbar.set_postfix({"loss": loss.item()}) def main(): # ============================== # Parse Arguments # ============================== parser = argparse.ArgumentParser() # FIXME(ver217): gemini is not supported resnet now parser.add_argument( "-p", "--plugin", type=str, default="torch_ddp", choices=["torch_ddp", "torch_ddp_fp16", "low_level_zero", "gemini"], help="plugin to use", ) parser.add_argument("-r", "--resume", type=int, default=-1, help="resume from the epoch's checkpoint") parser.add_argument("-c", "--checkpoint", type=str, default="./checkpoint", help="checkpoint directory") parser.add_argument("-i", "--interval", type=int, default=5, help="interval of saving checkpoint") parser.add_argument( "--target_acc", type=float, default=None, help="target accuracy. Raise exception if not reached" ) args = parser.parse_args() # ============================== # Prepare Checkpoint Directory # ============================== if args.interval > 0: Path(args.checkpoint).mkdir(parents=True, exist_ok=True) # ============================== # Launch Distributed Environment # ============================== colossalai.launch_from_torch() coordinator = DistCoordinator() # update the learning rate with linear scaling # old_gpu_num / old_lr = new_gpu_num / new_lr global LEARNING_RATE LEARNING_RATE *= coordinator.world_size # ============================== # Instantiate Plugin and Booster # ============================== booster_kwargs = {} if args.plugin == "torch_ddp_fp16": booster_kwargs["mixed_precision"] = "fp16" if args.plugin.startswith("torch_ddp"): plugin = TorchDDPPlugin() elif args.plugin == "gemini": plugin = GeminiPlugin(initial_scale=2**5) elif args.plugin == "low_level_zero": plugin = LowLevelZeroPlugin(initial_scale=2**5) booster = Booster(plugin=plugin, **booster_kwargs) # ============================== # Prepare Dataloader # ============================== train_dataloader, test_dataloader = build_dataloader(100, coordinator, plugin) # ==================================== # Prepare model, optimizer, criterion # ==================================== # resent50 model = torchvision.models.resnet18(num_classes=10) # Loss and optimizer criterion = nn.CrossEntropyLoss() optimizer = HybridAdam(model.parameters(), lr=LEARNING_RATE) # lr scheduler lr_scheduler = MultiStepLR(optimizer, milestones=[20, 40, 60, 80], gamma=1 / 3) # ============================== # Boost with ColossalAI # ============================== model, optimizer, criterion, _, lr_scheduler = booster.boost( model, optimizer, criterion=criterion, lr_scheduler=lr_scheduler ) # ============================== # Resume from checkpoint # ============================== if args.resume >= 0: booster.load_model(model, f"{args.checkpoint}/model_{args.resume}.pth") booster.load_optimizer(optimizer, f"{args.checkpoint}/optimizer_{args.resume}.pth") booster.load_lr_scheduler(lr_scheduler, f"{args.checkpoint}/lr_scheduler_{args.resume}.pth") # ============================== # Train model # ============================== start_epoch = args.resume if args.resume >= 0 else 0 for epoch in range(start_epoch, NUM_EPOCHS): train_epoch(epoch, model, optimizer, criterion, train_dataloader, booster, coordinator) lr_scheduler.step() # save checkpoint if args.interval > 0 and (epoch + 1) % args.interval == 0: booster.save_model(model, f"{args.checkpoint}/model_{epoch + 1}.pth") booster.save_optimizer(optimizer, f"{args.checkpoint}/optimizer_{epoch + 1}.pth") booster.save_lr_scheduler(lr_scheduler, f"{args.checkpoint}/lr_scheduler_{epoch + 1}.pth") accuracy = evaluate(model, test_dataloader, coordinator) if args.target_acc is not None: assert accuracy >= args.target_acc, f"Accuracy {accuracy} is lower than target accuracy {args.target_acc}" if __name__ == "__main__": main()