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b75b1f0bf1
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[algo] feat: add GSPO-token policy loss computation function (#2775)
### What does this PR do?
This PR implements the GSPO-token policy loss calculation proposed by
paper https://arxiv.org/pdf/2507.18071
### Test
<img width="1341" height="637" alt="image"
src="https://github.com/user-attachments/assets/bc5e2245-b0f5-4a1f-aa7c-4c2b28d95142"
/>
Compared GRPO and GSPO under the same settings. GRPO uses the following
script:
``` sh
python3 -m verl.trainer.main_ppo \
algorithm.adv_estimator=grpo \
data.train_files=$HOME/data/gsm8k/train.parquet \
data.val_files=$HOME/data/gsm8k/test.parquet \
data.train_batch_size=512 \
data.max_prompt_length=512 \
data.max_response_length=1024 \
data.filter_overlong_prompts=True \
data.truncation='error' \
actor_rollout_ref.model.path=Qwen/Qwen2.5-3B-Instruct \
actor_rollout_ref.actor.optim.lr=1e-6 \
actor_rollout_ref.model.use_remove_padding=True \
actor_rollout_ref.actor.ppo_mini_batch_size=128 \
actor_rollout_ref.actor.ppo_micro_batch_size_per_gpu=40 \
actor_rollout_ref.actor.use_kl_loss=True \
actor_rollout_ref.actor.kl_loss_coef=0.001 \
actor_rollout_ref.actor.kl_loss_type=low_var_kl \
actor_rollout_ref.actor.entropy_coeff=0 \
actor_rollout_ref.actor.policy_loss.loss_mode="vanilla" \
actor_rollout_ref.model.enable_gradient_checkpointing=True \
actor_rollout_ref.actor.fsdp_config.param_offload=False \
actor_rollout_ref.actor.fsdp_config.optimizer_offload=False \
actor_rollout_ref.rollout.log_prob_micro_batch_size_per_gpu=40 \
actor_rollout_ref.rollout.tensor_model_parallel_size=2 \
actor_rollout_ref.rollout.name=vllm \
actor_rollout_ref.rollout.gpu_memory_utilization=0.6 \
actor_rollout_ref.rollout.n=10 \
actor_rollout_ref.ref.log_prob_micro_batch_size_per_gpu=40 \
actor_rollout_ref.ref.fsdp_config.param_offload=True \
algorithm.use_kl_in_reward=False \
trainer.critic_warmup=0 \
trainer.logger='["console","wandb"]' \
trainer.project_name='verl_gspo_cmp' \
trainer.experiment_name='qwen2.5-3B-GRPO' \
trainer.n_gpus_per_node=8 \
trainer.nnodes=1 \
trainer.save_freq=20 \
trainer.test_freq=5 \
trainer.total_epochs=15 $@
```
GSPO uses the following script:
```sh
python3 -m verl.trainer.main_ppo \
algorithm.adv_estimator=grpo \
data.train_files=$HOME/data/gsm8k/train.parquet \
data.val_files=$HOME/data/gsm8k/test.parquet \
data.train_batch_size=512 \
data.max_prompt_length=512 \
data.max_response_length=1024 \
data.filter_overlong_prompts=True \
data.truncation='error' \
actor_rollout_ref.model.path=Qwen/Qwen2.5-3B-Instruct \
actor_rollout_ref.actor.optim.lr=1e-6 \
actor_rollout_ref.model.use_remove_padding=True \
actor_rollout_ref.actor.ppo_mini_batch_size=128 \
actor_rollout_ref.actor.ppo_micro_batch_size_per_gpu=40 \
actor_rollout_ref.actor.use_kl_loss=True \
actor_rollout_ref.actor.kl_loss_coef=0.001 \
actor_rollout_ref.actor.kl_loss_type=low_var_kl \
actor_rollout_ref.actor.entropy_coeff=0 \
actor_rollout_ref.actor.policy_loss.loss_mode="gspo" \
actor_rollout_ref.model.enable_gradient_checkpointing=True \
actor_rollout_ref.actor.fsdp_config.param_offload=False \
actor_rollout_ref.actor.fsdp_config.optimizer_offload=False \
actor_rollout_ref.rollout.log_prob_micro_batch_size_per_gpu=40 \
actor_rollout_ref.rollout.tensor_model_parallel_size=2 \
actor_rollout_ref.rollout.name=vllm \
actor_rollout_ref.rollout.gpu_memory_utilization=0.6 \
actor_rollout_ref.rollout.n=10 \
actor_rollout_ref.ref.log_prob_micro_batch_size_per_gpu=40 \
actor_rollout_ref.ref.fsdp_config.param_offload=True \
algorithm.use_kl_in_reward=False \
trainer.critic_warmup=0 \
trainer.logger='["console","wandb"]' \
trainer.project_name='verl_gspo_cmp' \
trainer.experiment_name='qwen2.5-3B-GRPO' \
trainer.n_gpus_per_node=8 \
trainer.nnodes=1 \
trainer.save_freq=20 \
trainer.test_freq=5 \
trainer.total_epochs=15 $@
```
### API and Usage Example
To use GSPO, users only need to set
`actor_rollout_ref.actor.policy_loss.loss_mode` to `gspo`.
```shell
python3 -m verl.trainer.main_ppo \
... \
actor_rollout_ref.actor.policy_loss.loss_mode="gspo" \
...
```
### Checklist Before Submitting
> [!IMPORTANT]
> Please check all the following items before requesting a review,
otherwise the reviewer might deprioritize this PR for review.
- [x] Read the [Contribute
Guide](https://github.com/volcengine/verl/blob/main/CONTRIBUTING.md).
- [x] Apply [pre-commit
checks](https://github.com/volcengine/verl/blob/main/CONTRIBUTING.md#code-linting-and-formatting):
`pre-commit install && pre-commit run --all-files --show-diff-on-failure
--color=always`
- [x] Add / Update [the
documentation](https://github.com/volcengine/verl/tree/main/docs).
- [x] Add unit or end-to-end test(s) to [the CI
workflow](https://github.com/volcengine/verl/tree/main/.github/workflows)
to cover all the code. If not feasible, explain why: ...
- [x] Once your PR is ready for CI, send a message in [the `ci-request`
channel](https://verl-project.slack.com/archives/C091TCESWB1) in [the
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(If not accessible, please try [the Feishu group
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---------
Co-authored-by: BounharAbdelaziz <bounhar.abdelaziz@gmail.com>
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2025-07-30 18:47:09 +08:00 |
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