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[Bugfix] BailingMoeV2.5: rotate full qk_rope_head_dim in MLA RoPE #41185

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Merged
ZJY0516 merged 4 commits into from
Apr 29, 2026
+8 −2
Merged

[Bugfix] BailingMoeV2.5: rotate full qk_rope_head_dim in MLA RoPE #41185

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ZJY0516 Apr 29, 2026
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ZJY0516 Apr 29, 2026
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Merge branch 'main' into fix-ling-accuracy
ZJY0516 Apr 29, 2026
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Merge branch 'main' into fix-ling-accuracy
ZJY0516 Apr 29, 2026
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10 changes: 8 additions & 2 deletions vllm/model_executor/models/bailing_moe_linear.py
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Original file line number Diff line number Diff line change
Expand Up @@ -205,13 +205,19 @@ def __init__(
self.q_a_layernorm = None
self.q_b_proj = None

rope_parameters = _build_rope_parameters(config)
rope_parameters = _build_rope_parameters(config) or {}
# MLA rotates the full qk_rope_head_dim,
# partial_rotary_factor is for the linear-attn head only.
rope_parameters = {
k: v for k, v in rope_parameters.items() if k != "partial_rotary_factor"
}
rope_parameters["rope_dim"] = self.qk_rope_head_dim
Comment on lines +211 to +214
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@gemini-code-assist gemini-code-assist Bot Apr 29, 2026

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high

The key rope_dim is not standard in vLLM's get_rope utility; the expected key to control the number of rotated dimensions is rotary_dim. While using rope_dim might appear to work because rotary_dim defaults to head_size (which is set to self.qk_rope_head_dim here), it would fail to override an existing rotary_dim if one were present in the model configuration. Additionally, the logic for filtering partial_rotary_factor can be simplified using .pop() for better readability.

        rope_parameters = _build_rope_parameters(config) or {}
        rope_parameters.pop("partial_rotary_factor", None)
        rope_parameters["rotary_dim"] = self.qk_rope_head_dim

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max_position = getattr(config, "max_position_embeddings", 8192)
self.rotary_emb = get_rope(
head_size=self.qk_rope_head_dim,
max_position=max_position,
is_neox_style=False,
rope_parameters=rope_parameters or None,
rope_parameters=rope_parameters,
)

# Build MLAModules for MultiHeadLatentAttentionWrapper
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