deepspeedai / deepspeedai/DeepSpeed
zero.Init partitioning of large fused MoE-expert tensors spikes a single GPU (transient full materialization) -> OOM during load even when the sharded model fits
Nobody has claimed this yet.
- Dominant language
- Python
- Stars
- 43.1k
- Forks
- 5k
- Avg merge
- 4d 15h
- Merged PRs (30d)
- 112
Description
Env: transformers 5.12.1, deepspeed 0.18.9, torch 2.12.0+cu130, peft 0.19.1, bitsandbytes 0.49.2, accelerate 1.14.0; 8x B200 (178GB) / 2TB RAM; model MiniMaxAI/MiniMax-M3 (428B sparse MoE VL, minimax_m3_vl).
During the correctly-sharded (world_size=8) load, a single GPU spikes to ~180GB vs the ~94GB steady partition and OOMs. The giant fused MoE-expert parameter (128 experts) appears to be materialized in full on a GPU before being scattered. This is a load-time transient — independent of sequence length — and offload_param: {device: cpu} does not prevent the GPU spike during the from_pretrained init path.
Ask: stream/scatter very large parameters during partitioning without a full single-GPU materialization, and honor remote_device='cpu' during the from_pretrained init path so the load can stage through CPU.
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
Reproduce the MiniMaxAI/MiniMax-M3 load with the stated DeepSpeed, PyTorch, and transformers environment, then trace the from_pretrained init path into zero.Init partitioning. Inspect how the giant fused MoE parameter is materialized and how remote_device='cpu' and offload_param are handled. Done means partitioning avoids a full single-GPU materialization and the sharded model loads without the transient OOM.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- python, pytorch
- Domain
- distributed-systems, machine-learning, performance
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Quiet
- Clarity
- Mostly clear
- Newbie friendliness
- 45/100