vllm-project/vllm · error · RuntimeError

Model: {} with config {} {} {} {} {} mismatch with new model

Error message

Model: {} with config {} {} {} {} {} mismatch with new model {} with config {} {} {} {}

What it means

Error "Model: {} with config {} {} {} {} {} mismatch with new model {} with config {} {} {} {}" thrown in vllm-project/vllm.

Source

Thrown at vllm/distributed/eplb/eplb_state.py:338

            i % num_routed_experts for i in range(num_redundant_experts)
        ]
        return global_physical_to_logical_map

    def validate_ep_configuration(self, new_model: MixtureOfExperts):
        """
        Validate that the expert parallel configuration of
        the new model is the same as the existing models.
        """
        if len(self.model_states) > 0:
            model = next(iter(self.model_states.values())).model
            if (
                model.num_routed_experts != new_model.num_routed_experts
                or model.num_redundant_experts != new_model.num_redundant_experts
                or model.num_physical_experts != new_model.num_physical_experts
                or model.num_logical_experts != new_model.num_logical_experts
                or model.num_expert_groups != new_model.num_expert_groups
            ):
                raise RuntimeError(
                    "Model: {} "
                    "with config {} "
                    "{} {} {} {} "
                    "mismatch with new model {} "
                    "with config {} "
                    "{} {} {} {}".format(
                        type(model),
                        model.num_routed_experts,
                        model.num_redundant_experts,
                        model.num_physical_experts,
                        model.num_logical_experts,
                        model.num_expert_groups,
                        type(new_model),
                        new_model.num_routed_experts,
                        new_model.num_redundant_experts,
                        new_model.num_physical_experts,
                        new_model.num_logical_experts,
                        new_model.num_expert_groups,

View on GitHub (pinned to c794754062)

Solutions

1. Ensure the new model and configuration match the loaded model's architecture and parallel config before reconfiguring EPLB state.

When it happens

Trigger: Raised at vllm/distributed/eplb/eplb_state.py:338 when validation fails: Model config mismatch with new model during elastic EP reconfiguration. Typically triggered by an incompatible or incomplete vLLM configuration, an unsupported platform/backend combination, or a runtime resource/dependency that is missing.

Common situations: Commonly encountered at vllm/distributed/eplb/eplb_state.py:338 during vLLM startup/config validation or runtime setup when: (1) conflicting CLI flags or config fields are combined, (2) the current platform (CUDA/ROCm/CPU/XPU) or installed optional packages do not support the requested feature, or (3) a required value is absent or out of range. Resolve by correcting the configuration as described in the message, or by selecting a supported alternative.

AI-assisted analysis of vllm-project/vllm@c794754062 (2026-08-14). Data as JSON: /api/errors/269e4065852ebf71. Report an issue: GitHub.