Service Parameter Optimizer

Overview

Service Parameter Optimizer (optix) is an automatic optimization tool for serving parameters based on Particle Swarm Optimization (PSO). It supports vLLM and MindIE, automatically tuning parameters to find the optimal throughput configuration that meets latency requirements.

The tool consists of two core functional modules:

• Parameter optimization module: uses PSO to automatically generate serving parameter combinations and iteratively approach the optimal solution. In addition, the Early Rejection algorithm performs early-stage benchmarks on serving parameters based on theoretical modeling, tuning experience, and partial test data.

• Parameter verification module: automatically starts the serving process and benchmark tool to test parameters and obtain performance results. Currently, the supported benchmark tools include ais_bench and vllm_benchmark.

Based on the modules above, Service Parameter Optimizer can automatically recommend serving parameter combinations that deliver high throughput.

The tool has been validated on LLaMA3-8B and Qwen3-8B. In principle, it does not limit the supported model types, and broader validation coverage is planned for future releases.

Concepts

• vLLM and MindIE: serving frameworks, which support model deployment in serving scenarios.
• vLLM_Benchmark and Ais_Bench: inference performance benchmark tools for serving frameworks.

Supported Products

Product Type	Supported (Yes/No)
Atlas A3 training products and Atlas A3 inference products	Yes
Atlas A2 training products and Atlas A2 inference products	Yes
Atlas 200I/500 A2 inference products	Yes
Atlas inference products	Yes
Atlas training products	No

Preparations

Environment Setup Set up an environment where serving tools (such as vLLM Server/MindIE Service) and benchmark tools (such as vllm_benchmark/ais_bench, see Benchmark Tool Deployment) can run properly.

Tool Installation

optix is integrated into the msmodeling package. Installation command:

pip install msmodeling

Tool Uninstallation

pip uninstall msmodeling

Quick Start

1. Complete the operations described in Preparations.

2. Modify the configuration file. Before starting optimization, configure config.toml according to your environment, including optimization parameters, benchmark tool parameters, and serving parameters. See Configuration File Description for details.

3. Start optimization. After the preceding steps are complete, start automatic optimization with a single command:

   msmodeling optix
   

   By default, the tool optimizes vLLM serving parameters with Ais_Bench as the benchmark tool.

4. View the results. The optimization time depends on the model size and dataset size, typically taking 4 to 8 hours. Upon completion, the data_storage_*.csv file is generated and saved in the result/store subdirectory under the current directory. The file records the performance of each parameter set. For details, see Output File Description.

Command Parameters

Function

By combining real-device testing with the parameter verification and optimization modules, the tool delivers reliable recommended values for serving parameters.

Precautions

None

Syntax

msmodeling optix [options]

Parameters

Parameter	Mandatory (Yes/No)	Description
-lb or --load_breakpoint	No	Specifies whether to resume optimization from a breakpoint. Including this parameter enables breakpoint resumption; omitting it disables this feature.
-d or --deploy_policy	No	Specifies a deployment policy. The options are as follows: •single: single-node deployment •multiple: multi-node deployment The default value is single.
--backup	No	Specifies whether to back up data during optimization. The options are as follows: • True: enables backup. • False: disables backup. The default value is False.
-b or --benchmark_policy	No	Specifies a benchmark tool. The options are as follows: •vllm_benchmark: vllm_benchmark is used as the benchmark tool. •ais_bench: ais_bench is used as the benchmark tool. The default value is ais_bench. You need to select a benchmark tool compatible with your inference framework.
-e or --engine	No	Specifies an inference framework. The options are as follows: •vllm: vLLM is used as the inference framework. •mindie: MindIE is used as the inference framework. The default value is vllm.
-c or --config	No	Specifies a custom configuration file path (TOML format). Supports the following three forms: •Absolute path: directly uses the specified path; •Relative path (with directory separators): resolves relative to the current working directory; •Filename only: searches in the current working directory. If not specified, the tool searches for configuration files in preset path order. The specified file must be in valid TOML format and has the highest configuration priority.

Example (vLLM Service Parameter Optimization)

1. Modify the configuration file. Before starting optimization, configure <idp:inline displayname="code" id="code151415418558">config.toml</idp:inline> according to your environment, including optimization parameters, benchmark tool parameters, and serving parameters. See Configuration File Description for details.

2. To set environment variables for the vLLM/MindIE services, configure them before running the tool. For example:

   export ASCEND_RT_VISIBLE_DEVICES=0
   

   The tool automatically applies these environment variables during optimization.

3. Once the prerequisites are ready, run the following command to start automatic optimization:

   msmodeling optix -e vllm
   

   To use vllm_benchmark in the vLLM scenario:

   msmodeling optix -e vllm -b vllm_benchmark
   

Example (MindIE Serving Parameter Optimization)

1. Modify the configuration file. Before starting optimization, configure <idp:inline displayname="code" id="code121419465514">config.toml</idp:inline> according to your environment, including optimization parameters, benchmark tool parameters, and serving parameters. See Configuration File Description for details.

2. To set environment variables for the vLLM/MindIE services, configure them before running the tool. For example:

   export ASCEND_RT_VISIBLE_DEVICES=0
   

   The tool automatically applies these environment variables during optimization.

3. Once the prerequisites are ready, run the following command to start automatic optimization:

   msmodeling optix -e mindie
   

Example (Specifying a Custom Configuration File)

If the configuration file is not in the default search path, you can explicitly specify it using the -c parameter:

# Absolute path
msmodeling optix -c /data/configs/my_config.toml

# Filename in the current directory
msmodeling optix -c my_config.toml

# Relative path
msmodeling optix -e vllm -b vllm_benchmark -c ../configs/vllm_config.toml

The specified configuration file has the highest priority and overrides configurations with the same name in the default path.

Output Description

After automatic optimization is complete, a result file in CSV format is generated and stored in the result/store folder in the current directory. For details, see Output File Description.

Output File Description

Each row in the output CSV corresponds to a parameter set, with the first four columns representing performance metrics. You can filter rows that meet your requirements and update vLLM/MindIE and vllm_benchmark/ais_bench parameters with the corresponding values from the CSV.

Field	Description
generate_speed	Throughput
time_to_first_token	Time to first token (TTFT), in seconds.
time_per_output_token	Time per output token (TPOT), in seconds.
success_rate	Request success rate
throughput	Test throughput, in requests per second.
CONCURRENCY	Concurrency
REQUESTRATE	Send rate
error	Records error reasons if parameters failed to execute.
backup	Data backup path (recorded when --backup is enabled)
real_evaluation	Specifies whether data is obtained from the actual test result. false indicates that the data is obtained from the GP model prediction.
fitness	Optimization score. Lower values indicate better parameter sets.
num_prompts	Number of requests sent by the benchmark tool.

Other columns are the config.toml parameters from vLLM or MindIE.

Appendixes

Configuration File Description

Optimization parameters: n_particles (number of optimization particles), iters (number of iterations), and tpot_slo (latency constraint for time_per_output_token). You can configure the number of particles and iterations based on the estimated time. Each particle requires time for service startup and testing. For example, if service startup and testing takes 9 to 10 minutes per run, and you allocate 8 hours for optimization, you can run approximately 50 particles in total. The recommended configuration is 5 × 10. That is, 10 particles and 5 iterations. As a rule of thumb, set the number of particles to about twice the number of iterations.

Note: All of the following optimization parameters are mandatory and must not be deleted or omitted. Otherwise, an error will occur during running.

Parameter	Mandatory (Yes/No)	Description
n_particles	Yes	Number of particles (parameter combinations). The value is an integer ranging from 1 to 1000. The recommended value ranges from 15 to 30.
iters	Yes	Number of iterations. The value is an integer ranging from 1 to 1000. The recommended value ranges from 5 to 10.
ttft_penalty	Yes	Penalty coefficient for time_to_first_token (TTFT) violations. Set it to 0 if there is no TTFT constraint. Value range: [0, 100]. The recommended value is 1.
tpot_penalty	Yes	Penalty coefficient for time_per_output_token (TPOT) violations. Set it to 0 if there is no TPOT constraint. Value range: [0, 100]. The recommended value is 1.
success_rate_penalty	Yes	Penalty coefficient for the request success rate. The value is an integer ranging from 1 to 1000. The recommended value is 5.
ttft_slo	Yes	TTFT latency constraint (in seconds) For example, if TTFT is limited to 2s, set the value to 2. Value range: (0, 100].
tpot_slo	Yes	TPOT latency constraint (in seconds) For example, if TPOT is limited to 50 ms, set the value to 0.05. Value range: (0, 100].
service	Yes	Node role in multi-node deployment. The options are as follows: •master: primary node •slave: secondary node The default value is master.
sample_size	No	Dataset sampling size for improved efficiency. The value is an integer ranging from 1000 to 10000. The recommended value is 1/3 of original dataset size.

Benchmark tool parameters: If ais_bench is used for the test, modify the following parameters. For details, see [ais_bench Usage Description] (https://gitee.com/aisbench/benchmark/blob/master/README.md).

Parameter	Description
models	Specifies a model task. You can configure it as described in [Model Configuration Description] (https://gitee.com/aisbench/benchmark/blob/master/doc/users_guide/models.md).
datasets	Specifies a dataset task. For details, see [Dataset Preparation Guide] (https://gitee.com/aisbench/benchmark/blob/master/doc/users_guide/datasets.md).
mode	Specifies the operation mode. For details, see Operation Mode Description.
num_prompts	Specifies the number of prompts to run from the dataset. This parameter is valid only when mode is set to perf.

If vllm_benchmark is used for the test, modify the following parameters:

Parameter	Mandatory (Yes/No)	Description
host	Yes	Host IP address, which must match host in [vllm.command]. The value can be 127.0.0.1.
port	Yes	Port number, which must match port in [vllm.command].
model	Yes	Model path, which must match model in [vllm.command].
served_model_name	Yes	Model name, which must match served_model_name in [vllm.command].
dataset_name	Yes	Dataset name
dataset_path	Yes	Dataset path
num_prompts	Yes	Specifies the number of prompts to run from the dataset. The value is an integer ranging from 1 to 10000.
others	No	Additional parameters. Use spaces to separate them, and no space is allowed within the parameters, for example, --ignore-eos --custom-output-len 1500. This parameter is left empty by default.

vLLM serving parameters: When the vLLM framework is used, you need to modify the [vllm.command] parameter in the config.toml file. For example:

[vllm.command]
host = "127.0.0.1"
port = "8000"
model = "/workspace/vllm/models/llama-2-7b-chat-hf"
served_model_name = "llama-2-7b-chat-hf"
others = ""

Parameter	Mandatory (Yes/No)	Description
host	Yes	Host IP address, which must match host in [vllm_benchmark.command]. The value can be 127.0.0.1.
port	Yes	Port number, which must match port in [vllm_benchmark.command].
model	Yes	Model path, which must match model in [vllm_benchmark.command].
served_model_name	Yes	Model name, which must match served_model_name in [vllm_benchmark.command].
others	No	Additional parameters. Use spaces to separate them, and no space is allowed within the parameters, for example, --tensor-parallel-size 2 --no-enable-prefix-caching. This parameter is left empty by default.

vLLM Custom Parameter Optimization

The optimizer supports adding any vLLM startup parameter for optimization through [[vllm.target_field]]. The configuration involves two steps: declaring the optimization field and referencing the variable in others.

Variable reference rule: Use the format $UPPERCASE_FIELD_NAME in others to reference an optimization field. The tool automatically replaces it with the actual value of the current iteration.

Example 1: Enumerated Numeric Parameter (Taking gpu_memory_utilization as an Example)

Step 1: Declare the optimization field.

[[vllm.target_field]]
name = "GPU_MEMORY_UTILIZATION"
config_position = "env"
dtype = "enum"
dtype_param = [0.9, 0.91, 0.92]
value = 0.9

Step 2: Reference the variable in others of [vllm.command].

[vllm.command]
# ... other mandatory parameters ...
others = "--gpu-memory-utilization $GPU_MEMORY_UTILIZATION"

Example 2: Switch/Composite String Parameter (Taking Compilation Config --compilation-config as an Example)

When the parameter itself is a complete CLI string, you can use an empty string "" (not enabled) and the enabled form as enum candidates. The tool automatically skips empty strings and does not append anything to the launch command.

Step 1: Declare the optimization field.

Note: TOML uses double quotation marks " as string delimiters. If the string content contains double quotation marks, use \" to escape them. Otherwise, a parsing error will occur.

[[vllm.target_field]]
name = "COMPILATION_CONFIG"
config_position = "env"
dtype = "enum"
dtype_param = ["", "--compilation-config '{\"cudagraph_mode\": \"FULL_DECODE_ONLY\"}'"]
value = "--compilation-config '{\"cudagraph_mode\": \"FULL_DECODE_ONLY\"}'"

Step 2: Reference the variable in others of [vllm.command].

[vllm.command]
# ... other mandatory parameters ...
others = "$COMPILATION_CONFIG"

MindIE serving parameters: Modify these parameters as described in [MindIE Server Configuration Parameter Description] (https://www.hiascend.com/document/detail/zh/mindie/20RC1/mindieservice/servicedev/mindie_service0285.html). You can define search ranges directly using these parameters. For example, to set the optimization search space for max_batch_size to 10 to 400:

[[mindie.target_field]]
name = "max_batch_size" # Serving parameter name
config_position = "BackendConfig.ScheduleConfig.maxBatchSize" # Path to the serving parameters in MindIE Server config
min = 10 # Minimum value
max = 400 # Maximum value
dtype = "int" # Data type

You can also define parameters relative to others. For example, to set max_prefill_batch_size as a ratio of max_batch_size, that is, max_prefill_batch_size = ratio * max_batch_size (0 < ratio < 1):

[[mindie.target_field]]
name = "max_prefill_batch_size"
config_position = "BackendConfig.ScheduleConfig.maxPrefillBatchSize"
min = 0
max = 1
dtype = "ratio"
dtype_param = "max_batch_size" # Indicates that max_prefill_batch_size is proportional to max_batch_size.

Plugin Mode

Service Parameter Optimizer supports user-defined search parameter configuration and benchmark tools. You can configure them as needed by adapting to the plugin interface and registering the corresponding plugin. For details, see Plugin Development Guide.

Log Description

The default log level during optimization is INFO. To view detailed per-iteration logs, set the following environment variable before running the tool:

export MODELEVALSTATE_LEVEL=DEBUG

The status of each iteration is printed to the console. Detailed vLLM/MindIE logs are redirected to /tmp. The exact file path is shown in the console output for debugging service status.