# Model Randomness Introduced by DDP **URL:** \ **Category:** 🤗Transformers\ **Created:** [June 12, 2024, 9:41pm UTC](https://discuss.huggingface.co/t/model-randomness-introduced-by-ddp/91845 "2024-06-12T21:41:58Z")\ **Posts on this page:** 2\ **Page:** 1
**Author:** ![rirv938](https://sea2.discourse-cdn.com/hellohellohello/user_avatar/discuss.huggingface.co/rirv938/32/27753_2.png) [@rirv938](https://discuss.huggingface.co/u/rirv938)\ **Post date:** [June 12, 2024, 9:41pm UTC](https://discuss.huggingface.co/t/model-randomness-introduced-by-ddp/91845/1 "2024-06-12T21:41:58Z")
I am using the huggingface Trainer with DDP I am trying to debug why performance is worse the more GPUs I add to training. I noticed this weird behaviour. I train on a single batch of 8 values and print out the loss on each value. i) gradient accumulation 8 AND 1 GPU ii) gradient accumulation 1 AND 8 GPUs notice how the only dataset value they agree on the loss is the 0th GPU input. Its as if there is some additional randomness associated with the GPU number “dataset” value is a hash of the input text in each case. ```auto 8 GPUs:: {'loss': 0.7977094054222107, 'losses': tensor([[0.7977]], device='cuda:0', grad_fn=), 'dataset': [1277834], 'rank': '0', 'local_rank': '0'} {'loss': 0.012322795577347279, 'losses': tensor([[0.0123]], device='cuda:1', grad_fn=), 'dataset': [1273165], 'rank': '1', 'local_rank': '1'} {'loss': 1.1729881763458252, 'losses': tensor([[1.1730]], device='cuda:2', grad_fn=), 'dataset': [1406156], 'rank': '2', 'local_rank': '2'} {'loss': 0.4811226427555084, 'losses': tensor([[0.4811]], device='cuda:3', grad_fn=), 'dataset': [1847032], 'rank': '3', 'local_rank': '3'} {'loss': 7.391242027282715, 'losses': tensor([[7.3912]], device='cuda:4', grad_fn=), 'dataset': [1082392], 'rank': '4', 'local_rank': '4'} {'loss': 4.4031829833984375, 'losses': tensor([[4.4032]], device='cuda:5', grad_fn=), 'dataset': [900771], 'rank': '5', 'local_rank': '5'} {'loss': 0.451646625995636, 'losses': tensor([[0.4516]], device='cuda:6', grad_fn=), 'dataset': [1196583], 'rank': '6', 'local_rank': '6'} {'loss': 1.757645606994629, 'losses': tensor([[1.7576]], device='cuda:7', grad_fn=), 'dataset': [986218], 'rank': '7', 'local_rank': '7'} 1 gpu (grad acc 8):: same: {'loss': 0.7977094054222107, 'losses': tensor([[0.7977]], device='cuda:0', grad_fn=), 'dataset': [1277834], 'rank': '0', 'local_rank': '0'} different: {'loss': 0.019877666607499123, 'losses': tensor([[0.0199]], device='cuda:0', grad_fn=), 'dataset': [1273165], 'rank': '0', 'local_rank': '0'} {'loss': 0.514133095741272, 'losses': tensor([[0.5141]], device='cuda:0', grad_fn=), 'dataset': [1406156], 'rank': '0', 'local_rank': '0'} {'loss': 0.147588849067688, 'losses': tensor([[0.1476]], device='cuda:0', grad_fn=), 'dataset': [1847032], 'rank': '0', 'local_rank': '0'} {'loss': 4.904898643493652, 'losses': tensor([[4.9049]], device='cuda:0', grad_fn=), 'dataset': [1082392], 'rank': '0', 'local_rank': '0'} {'loss': 0.6921711564064026, 'losses': tensor([[0.6922]], device='cuda:0', grad_fn=), 'dataset': [900771], 'rank': '0', 'local_rank': '0'} {'loss': 0.2580835819244385, 'losses': tensor([[0.2581]], device='cuda:0', grad_fn=), 'dataset': [1196583], 'rank': '0', 'local_rank': '0'} {'loss': 0.19682921469211578, 'losses': tensor([[0.1968]], device='cuda:0', grad_fn=), 'dataset': [986218], 'rank': '0', 'local_rank': '0'} ``` ---
**Author:** ![system](https://us1.discourse-cdn.com/hellohellohello/original/2X/d/de4155eb4aa4108ecb32a1389d7cc37ae69f88b7.png) [@system](https://discuss.huggingface.co/u/system)\ **Post date:** [June 13, 2024, 10:41am UTC](https://discuss.huggingface.co/t/model-randomness-introduced-by-ddp/91845/4 "2024-06-13T10:41:54Z")
Closed on June 13, 2024, 10:41am UTC This topic was automatically closed 12 hours after the last reply. New replies are no longer allowed.