Add AutoEP (#7938)
This PR adds AutoEP (Automatic Expert Parallelism) to DeepSpeed training
for HuggingFace MoE models.
AutoEP detects MoE blocks during `deepspeed.initialize()`, builds the
required EP/EDP process groups, and replaces supported MoE blocks with
an EP-enabled execution path, so expert parallelism can be enabled with
DeepSpeed config only and without model code changes.
Current scope in this PR is the base AutoEP feature:
- ZeRO stages 0, 1, and 2 support
- checkpoint save/load support
- universal checkpoint conversion support
ZeRO-3 extensions are intentionally left as follow-up work (#7928 should
be merged for this work)
Supported presets in this PR:
- Mixtral
- Qwen3-MoE
- DeepSeek-V2
- DeepSeek-V3
For end-to-end benchmarking and testing, an AutoEP example is available
in DeepSpeedExamples:
-
<https://github.com/tohtana/DeepSpeedExamples/tree/tohtana/add_auto_ep/training/expert_parallel>
## Attribution
This implementation substantially builds on TorchTitan's MoE /
expert-parallel implementation, and we want to explicitly acknowledge
that prior work.
The TorchTitan-derived pieces in this PR are primarily:
- `deepspeed/moe/ep_router.py`: adapted from TorchTitan's
`TokenChoiceTopKRouter`
- `deepspeed/moe/ep_experts.py`: adapted from TorchTitan's
`GroupedExperts` and grouped-GEMM expert execution path
- `deepspeed/moe/ep_kernels.py`: adapted from TorchTitan's
`TokenReorderer`, `generate_permute_indices`, Triton fill-indices
kernel, and token-group alignment / padding helpers
- `deepspeed/module_inject/auto_ep_layer.py`: adapts the same router ->
reorder -> dispatch -> local expert compute -> combine structure used in
TorchTitan's MoE / EP flow
Relevant TorchTitan sources:
-
<https://github.com/pytorch/torchtitan/blob/main/torchtitan/models/common/moe/moe.py>
-
<https://github.com/pytorch/torchtitan/blob/main/torchtitan/models/common/moe/kernels.py>
-
<https://github.com/pytorch/torchtitan/blob/main/torchtitan/models/common/moe/utils.py>
-
<https://github.com/pytorch/torchtitan/blob/main/torchtitan/distributed/expert_parallel.py>
The DeepSpeed-specific work in this PR is the AutoEP integration layer
around those building blocks:
- HuggingFace MoE detection and structural validation
- model-family presets and custom-config path
- weight repacking from HF expert layouts into grouped expert tensors
- DeepSpeed runtime group setup and module replacement
- DeepSpeed checkpoint save/load and universal checkpoint support
- DeepSpeed docs and tests
## Design
The implementation is split into a few layers:
- `deepspeed/module_inject/auto_ep_config.py`
- user config parsing
- built-in model presets
- validation for EP topology and per-model constraints
- `deepspeed/module_inject/auto_ep.py`
- scans the model for MoE blocks
- validates the detected structure
- builds a `MoELayerSpec` for each supported MoE layer
- replaces the original HF block with `AutoEPMoELayer`
- `deepspeed/module_inject/auto_ep_layer.py`
- the drop-in execution wrapper for a detected MoE block
- implements router execution, token reorder, EP dispatch/combine, local
expert compute, and shared-expert merge
- `deepspeed/moe/ep_router.py`, `deepspeed/moe/ep_experts.py`,
`deepspeed/moe/ep_kernels.py`
- reusable MoE runtime pieces for routing, grouped expert compute, token
permutation, and aligned grouped-GEMM execution
- `deepspeed/moe/ep_repack.py`
- converts HF expert weights into the grouped expert layout expected by
the runtime
- `deepspeed/runtime/engine.py` and checkpoint conversion code
- wires AutoEP into `deepspeed.initialize()`
- handles checkpoint save/load metadata and universal checkpoint
integration
At runtime, the execution path is:
1. detect and replace supported HF MoE blocks during initialization
2. route tokens with the EP router
3. reorder tokens by expert assignment
4. perform all-to-all dispatch across the EP group when `autoep_size >
1`
5. run local grouped expert compute
6. all-to-all combine and restore the original token order
7. merge shared experts if the model has them
## Adding new model support
There are two supported ways to extend AutoEP to a new MoE model family.
1. Add a preset in `PRESET_MODELS`.
This is the preferred path for a model family we want to support out of
the box. A preset defines:
- MoE layer pattern
- router child name
- experts child name
- expert weight names / layout
- `num_experts` and `top_k` config attributes
- routing defaults
- optional shared-expert structure
2. Use the custom config path.
For models that are not yet built into DeepSpeed, AutoEP can be driven
from config with:
- `moe_layer_pattern`
- `router_pattern`
- `expert_pattern`
- `expert_w1`, `expert_w2`, `expert_w3`
- `num_experts_attr`
- `top_k_attr`
- optional shared-expert fields
Once detection can produce a valid `MoELayerSpec`, the replacement,
execution, and checkpoint paths are shared.
---------
Signed-off-by: Masahiro Tanaka <mtanaka@anyscale.com>
Signed-off-by: Ma, Guokai <guokai.ma@gmail.com>
Signed-off-by: Guokai Ma <guokai.ma@intel.com>
Co-authored-by: Ma, Guokai <guokai.ma@gmail.com>
Co-authored-by: Guokai Ma <guokai.ma@intel.com>
