[Feature]: Add diff seeds to diff ranks and set torch seed in worker_init_fn (#1362)

mmseg/datasets/builder.py

@@ -186,3 +186,4 @@ def worker_init_fn(worker_id, num_workers, rank, seed):
     worker_seed = num_workers * rank + worker_id + seed
     np.random.seed(worker_seed)
     random.seed(worker_seed)
+    torch.manual_seed(worker_seed)

tools/train.py

@@ -8,6 +8,7 @@ import warnings
 
 import mmcv
 import torch
+import torch.distributed as dist
 from mmcv.cnn.utils import revert_sync_batchnorm
 from mmcv.runner import get_dist_info, init_dist
 from mmcv.utils import Config, DictAction, get_git_hash
@@ -50,6 +51,10 @@ def parse_args():
         help='id of gpu to use '
         '(only applicable to non-distributed training)')
     parser.add_argument('--seed', type=int, default=None, help='random seed')
+    parser.add_argument(
+        '--diff_seed',
+        action='store_true',
+        help='Whether or not set different seeds for different ranks')
     parser.add_argument(
         '--deterministic',
         action='store_true',
@@ -180,6 +185,7 @@ def main():
 
     # set random seeds
     seed = init_random_seed(args.seed)
+    seed = seed + dist.get_rank() if args.diff_seed else seed
     logger.info(f'Set random seed to {seed}, '
                 f'deterministic: {args.deterministic}')
     set_random_seed(seed, deterministic=args.deterministic)