Performance profiler

Introduction

The Simulation Framework provides a built-in performance profiler, which can help measure the CPU resources consumed by each of your activities for a particular simulation run.

Use cases for the profiler:

Measure the performance for specific environments and scenario executions
Measure the impact of features being added or removed in user defined activities and/or fmus
Compare two versions of activities

Enable and configure profiler

Based on the configuration, the data is either logged in the .log files or sent out to the opentelemetry collector endpoint.

Basic configuration

Add the following configuration to the simulation_scheduling section of your configuration file:

[1] To produce text based logs:

{
  "sim_instance_name": "test_simulation_instance",
  "profiler": 
  {
    "enabled": true
  },

[2] To send metrics to your active opentelemetry collector endpoint:

{
  "sim_instance_name": "test_simulation_instance",
  "profiler": 
  {
    "enabled": true,
    "otlp_endpoint": "127.0.0.1:4318"
  },
  "activities": [

Configuration parameters

The profiler section contains the following parameters:

Parameter	Type	Required	Description
`enabled`	boolean	Yes	Enables or disables the profiler, `false` if not specified.
`otlp_endpoint`	string	No	Opentelemetry collector endpoint. Refer: Example configuration

The profiler produces text based logs in the configured output_directory based on the configuration.
If the opentelemetry endpoint configured is of incorrect format then the profiler will produce text based logs.
If the profiler section is missing in the simulation_scheduling or enabled flag is set to false then the profiler stays disabled.
If the opentelemtry endpoint is unreachable an error will be thrown in the CLI output. Please make sure the endpoint is ready and active before running the simulation. Refer: Troubleshooting

Profiler behavior

Initialisation: All activities from simulation configuration are identified for profiling.
Collect Telemetry Data: Accumulate CPU usage times for each of the activities in the configuration during the run.
Report: CPU usage times for respective activities are reported either via text based logs or opentelemetry metrics based on your configuration.

Example configuration

Here's a complete Simfwk configuration example:

{
  "simulation_parameters": {
    "input_open_scenario": "../common/data/scenario/simple_cut_in.xosc",
    "input_user_settings": "../common/data/gtgen_usersettings/UserSettings.ini",
    "output_directory": "sim_output",
    "job_id": "autonomy_my_tpm_example"
  },
  "simulation_scheduling": {
    "sim_instance_name": "my_tpm_instance",
    "profiler": 
    {
      "enabled": true,
      "otlp_endpoint": "localhost:4318"
    },
    "activities": [
      {
        "name": "groundtruth_generator_activity",
        "is_primary_activity": true,
        "topics_cycling_info": [
          {
            "topic_id": "__all__",
            "topic_cycle_time_in_ms": 500
          }
        ],
        "type": "built-in"
      },
      {
        "name": "my_tpm_activity",
        "depends_on": ["groundtruth_generator_activity"],
        "type": "standalone"
      },
      {
        "name": "kpi_evaluator_activity",
        "depends_on": ["groundtruth_generator_activity"],
        "type": "built-in"
      },
      {
        "name": "kpi_logger_activity",
        "depends_on": ["kpi_evaluator_activity"],
        "type": "built-in"
      }
    ]
  }
}

Troubleshooting

If your Opentelemetry metrics are not received and you see errors in the simfwk_cli logs as shown below, this means your opentelemetry endpoint is not accessible. Please check your connections.

[Error] File: external/opentelemetry-cpp~/exporters/otlp/src/otlp_http_client.cc:213 [OTLP HTTP Client] Session state: connection failed.Failed to connect to localhost port 4318 after 0 ms: Couldn't connect to server

[Error] File: external/opentelemetry-cpp~/exporters/otlp/src/otlp_http_metric_exporter.cc:203 [OTLP METRIC HTTP Exporter] ERROR: Export 3 metric(s) error: 1

AVxcelerate Simulation Framework 2025 R2 SP02