Performance Analysis (Latency)#

This guide will help you add environment variables to enable GST TRACER logs and store results in a file. By analyzing these logs, you can monitor pipeline performance metrics, identify potential bottlenecks, and optimize the pipeline for better efficiency.

Steps to enable GST TRACER logging#

  1. Add the following environment variables to the dlstreamer-pipeline-server service in the docker-compose.yml file

    1. GST_DEBUG

    2. GST_TRACERS

    3. GST_DEBUG_FILE

    Example

    services:
  dlstreamer-pipeline-server:
    image: ${DLSTREAMER_PIPELINE_SERVER_IMAGE}
    environment:
      ...
      - GST_DEBUG=GST_TRACER:7
      - GST_TRACERS=latency_tracer(flags=element+pipeline)
      - GST_DEBUG_FILE=/tmp/trace.log
      ...
    volumes:
      - "/tmp:/tmp"

    • GST_DEBUG=GST_TRACER:7 indicates that GStreamer is set to log trace messages at level 7 during a pipeline’s execution.

    • GST_TRACERS=latency_tracer(flags=element+pipeline) instructs GStreamer to enable the DL Streamer latency tracer. flags=element+pipeline specifies that the tracer should measure latency for both the entire pipeline and individual elements within it.

    • GST_DEBUG_FILE=/tmp/trace.log specifies the file where the logs will be written.

  2. Start the Docker containers

    docker compose up -d

  3. Start a pipeline instance using the POST /pipelines/{name}/{version} endpoint

    • Refer to the “Send a REST request to run the default Pallet Defect Detection pipeline” step in the Get Started Guide for an example.

  4. View the logs

    • The GST TRACER logs are written to the trace.log file in the tmp directory. Since the tmp directory in the container is mounted to the local tmp directory, you can view the logs on your host machine.

    • To view the contents of the file, use cat trace.log

    • To follow the logs being written real-time, use tail -f trace.log Latency tracer is the functionality provided by DL Streamer. Please refer to the DL Streamer Latency Tracer documentation for available configuration options and detailed description of latency logs interpretation.

Learn More#

For more information on the Gstreamer tracing and debug log levels, refer to the following links:

Known Issues#

Issue: The trace.log file will be overwritten every time a pipeline related operation is executed.

  • Workaround: Copy the log file as needed.

Issue: The pipeline latency measurement does not work when gvametapublish element is in the pipeline.

  • Workaround: Leverage element latency.