xc-llm-ascend/docs/source/user_guide/configuration/additional_config.md

Additional Configuration

Additional configuration is a mechanism provided by vLLM to allow plugins to control inner behavior by themselves. VLLM Ascend uses this mechanism to make the project more flexible.

How to use

With either online mode or offline mode, users can use additional configuration. Take Qwen3 as an example:

Online mode:

vllm serve Qwen/Qwen3-8B --additional-config='{"config_key":"config_value"}'

Offline mode:

from vllm import LLM

LLM(model="Qwen/Qwen3-8B", additional_config={"config_key":"config_value"})

Configuration options

The following table lists additional configuration options available in vLLM Ascend:

Name	Type	Default	Description
xlite_graph_config	dict	{}	Configuration options for xlite graph mode
weight_prefetch_config	dict	{}	Configuration options for weight prefetch
refresh	bool	false	Whether to refresh global Ascend configuration content. This is usually used by rlhf or ut/e2e test case.
expert_map_path	str	None	When using expert load balancing for an MoE model, an expert map path needs to be passed in.
kv_cache_dtype	str	None	When using the KV cache quantization method, KV cache dtype needs to be set, currently only int8 is supported.
enable_shared_expert_dp	bool	False	When the expert is shared in DP, it delivers better performance but consumes more memory. Currently only DeepSeek series models are supported.
lmhead_tensor_parallel_size	int	None	The custom tensor parallel size of lmhead.
oproj_tensor_parallel_size	int	None	The custom tensor parallel size of oproj.
multistream_overlap_shared_expert	bool	False	Whether to enable multistream shared expert. This option only takes effect on MoE models with shared experts.
dynamic_eplb	bool	False	Whether to enable dynamic EPLB.
num_iterations_eplb_update	int	400	Forward iterations when EPLB begins.
gate_eplb	bool	False	Whether to enable EPLB only once.
num_wait_worker_iterations	int	30	The forward iterations when the EPLB worker will finish CPU tasks. In our test default value 30 can cover most cases.
expert_map_record_path	str	None	When dynamic EPLB is completed, save the current expert load heatmap to the specified path.
init_redundancy_expert	int	0	Specify redundant experts during initialization.
dump_config	str	None	Configuration file path for msprobe dump(eager mode).

The details of each configuration option are as follows:

xlite_graph_config

Name	Type	Default	Description
enabled	bool	False	Whether to enable xlite graph mode. Currently only Llama or Qwen dense series models are supported.
full_mode	bool	False	Whether to enable xlite for both the prefill and decode stages. By default, xlite is only enabled for the decode stage.

weight_prefetch_config

Name	Type	Default	Description
enabled	bool	False	Whether to enable weight prefetch.
prefetch_ratio	dict	{"attn": {"qkv": 1.0, "o": 1.0}, "moe": {"gate_up": 0.8}}	Prefetch ratio of each weight.

Example

An example of additional configuration is as follows:

{
    "weight_prefetch_config": {
        "enabled": True,
        "prefetch_ratio": {
            "attn": {
                "qkv": 1.0,
                "o": 1.0,
            },
            "moe": {
                "gate_up": 0.8
            }
        },
    },
    "multistream_overlap_shared_expert": True,
    "refresh": False,
}