Skip to content

Qwen2vl float16 inference bug in naive attention #35151

@kjohew

Description

@kjohew

System Info

  • transformers version: 4.46.2
  • Platform: Linux-5.15.0-125-generic-x86_64-with-glibc2.35
  • Python version: 3.10.15
  • Huggingface_hub version: 0.26.3
  • Safetensors version: 0.4.5
  • Accelerate version: 1.1.1
  • Accelerate config: not found
  • PyTorch version (GPU?): 2.5.1+cu124 (True)
  • Tensorflow version (GPU?): not installed (NA)
  • Flax version (CPU?/GPU?/TPU?): not installed (NA)
  • Jax version: not installed
  • JaxLib version: not installed
  • Using distributed or parallel set-up in script?:
  • Using GPU in script?:
  • GPU type: NVIDIA A10

Who can help?

@ArthurZucker @GeLee-Q

Information

  • The official example scripts
  • My own modified scripts

Tasks

  • An officially supported task in the examples folder (such as GLUE/SQuAD, ...)
  • My own task or dataset (give details below)

Reproduction

Hi @ArthurZucker @GeLee-Q , thanks for #33312, which has resolved the inference bug for qwen2vl in float16. However, it still has some flaws. Although the current code solves the numerical overflow issue, it may break causality of the autoregressive model. See details here.

Expected behavior

Current: Code

        if attention_mask is not None:  # no matter the length, we just slice it
            causal_mask = attention_mask[:, :, :, : key_states.shape[-2]]
            attn_weights = attn_weights + causal_mask

        # Fix precision issues in Qwen2-VL float16 inference
        # Replace inf values with zeros in attention weights to prevent NaN propagation
        if query_states.dtype == torch.float16:
            attn_weights = torch.where(torch.isinf(attn_weights), torch.zeros_like(attn_weights), attn_weights)

Fixed: Replace ±inf with zero before adding attn_weights with causal_mask. (prevent converting -inf, which for causality, to zero.)

        # Fix precision issues in Qwen2-VL float16 inference
        # Replace inf values with zeros in attention weights to prevent NaN propagation
        if query_states.dtype == torch.float16:
            attn_weights = torch.where(torch.isinf(attn_weights), torch.zeros_like(attn_weights), attn_weights)

        if attention_mask is not None:  # no matter the length, we just slice it
            causal_mask = attention_mask[:, :, :, : key_states.shape[-2]]
            attn_weights = attn_weights + causal_mask

Metadata

Metadata

Assignees

No one assigned

    Labels

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

    Development

    No branches or pull requests

    Issue actions