Lightning-AI / Lightning-AI/pytorch-lightning
Add support for `torchshard`
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- Dominant language
- Python
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- Avg merge
- 6d 7h
- Merged PRs (30d)
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Description
## 🚀 Feature
[torchshard](https://github.com/KaiyuYue/torchshard) is a newly and simple library for model parallel. In some case, we need to split one very large layer (larger than one gpu) to multiple gpus, and `torchshard` seems a simple solution.
Here's one of my use-case:
1. I have a very large tensor (9M*1024), aka. `VeryLargeTensor`, which is the representation vectors of 9M examples pre-computed from their features.
2. Given a new example `e`, I use model `Model` to generate `e`'s representation `v`(1*1024).
3. I need to compute dot-product similarity between `v` and `VeryLargeTensor`, and get a 9M*1 score tensor. However, `VeryLargeTensor` is so large that it must be split into multiple gpus.
4. During training, only `Model` is updated. `VeryLargeTensor` is always freezed and never updated.
5. (Since `VeryLargeTensor` is a plug-in tensor and not updated, I don't want to register it as `Model`'s parameter.)6.
6. If I split `VeryLargeTensor` in to multiple gpus, I do not need DP or DDP.
I think `torchshard` is a simple solution for my use-case. Or, is there better solution in pytorch-lightning?
### Motivation
### Pitch
### Alternatives
### Additional context
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cc @borda @akihironitta @justusschock
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reviewing the torchshard project linked in the issue and the repository's existing distributed training support. Clarify whether support means integration, documentation, or an alternative approach for sharding a frozen tensor across GPUs; the issue is complete only after that scope and an acceptance criterion are defined.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python, pytorch
- Domain
- distributed-systems, machine-learning
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100