How to Benchmark Performance#

This document provides instructions on how to run performance benchmarks for the Vision AI applications using the provided benchmarking scripts. The script determines the maximum number of concurrent video streams a system can process (stream density) while maintaining a target performance level.

Prerequisites#

  • The edge-ai-suites repository must be cloned to your system.

  • curl, jq, gawk, ffmpeg, and bc utilities installed

Step 1: Understand the Benchmarking Script#

The core of the benchmarking process is the benchmark_start.sh script, located in the metro-vision-ai-app-recipe/ directory. This script automates the process of starting video streams, monitoring their performance (Frames Per Second - FPS), and calculating key performance indicators (KPIs) to find the maximum sustainable stream density.

Stream Density Logic#

The script uses a binary search algorithm to efficiently find the optimal stream count within a given range (lower_bound and upper_bound). Here is a summary of the logic from the benchmark_start.sh script:

  1. Initialization: The script starts with a lower bound (lns) and an upper bound (uns) for the number of streams. The current number of streams to test (ns) is initialized to the lower bound. A variable (tns) tracks the highest successful stream count found so far.

  2. Binary Search Loop: The script iterates until the range between the lower and upper bounds is 1, and both bounds have been tested. In each iteration:

    • It runs a workload with the current number of streams (ns).

    • It measures the throughput min (the lowest FPS achieved among all streams) and compares it to the target_fps.

  3. Adjusting the Range:

    • If Performance Target is NOT Met (throughput min < target_fps): The current stream count (ns) is too high. It becomes the new upper bound (uns = ns). The next stream count to test is calculated as the midpoint between the old lower bound and this new upper bound.

    • If Performance Target is Met (throughput min >= target_fps): The system can handle this workload. The current stream count (ns) becomes the new lower bound (lns = ns), and the highest successful stream count (tns) is updated. The next stream count to test is calculated as the midpoint between this new lower bound and the old upper bound.

  4. Convergence: This process of testing midpoints and narrowing the search range continues until the loop condition is met. The final value of tns represents the highest number of streams that successfully met the performance target, which is reported as the final stream density.

Average FPS Calculation#

During each test run, the script logs the avg_fps for every active pipeline instance at regular intervals. At the end of the run, an awk script processes these logs to calculate several KPIs for the collection of FPS samples from each stream:

  • Percentile Throughput: Calculates a specific percentile (e.g., 90th) of the FPS values to ignore outliers.

  • Average Throughput: The mean FPS across all streams.

  • Median Throughput: The median FPS value.

  • Cumulative Throughput: The sum of the FPS from all streams.

  • Min Throughput: The lowest (worst-case) FPS achieved among all streams. This value is critical for the stream density calculation.

Step 2: Prepare for Benchmarking#

  1. Set Up and Start the Application: Before running the benchmark, you must set up and start the desired application (e.g., Smart Parking). This ensures all services, including the DL Streamer Pipeline Server, are running and available. For setup instructions, please refer to the get-started.md guide located in the specific application’s documentation folder (e.g., smart-parking/docs/user-guide/).

  2. Navigate to Script Directory: Open a terminal and navigate to the metro-vision-ai-app-recipe directory.

    cd edge-ai-suites/metro-ai-suite/metro-vision-ai-app-recipe/

  3. Stop Existing Pipelines: Ensure no other pipelines are running before you start the benchmark. You can stop any running pipelines with the sample_stop.sh script.

    ./sample_stop.sh

Step 3: Run the Benchmark#

Note: The default parameters are set based on best know methods recommended by Edge Workloads and Benchamarks group for workload with similar characteristics. These parameters can be modified when starting the pipelines.

The benchmark_start.sh script requires a pipeline name and stream count boundaries to run. The available pipelines are defined in the benchmark_app_payload.json file located within each application’s directory (e.g., smart-parking/).

Example Payload with Detection and Classification

The benchmark_app_payload.json file contains an array of pipeline configurations. Each configuration specifies the pipeline name and a payload with parameters for source, destination, and AI models. The script uses the pipeline name to select the corresponding payload for benchmarking.

Here is an example of a GPU pipeline configuration that includes both detection-properties and classification-properties with additional parameters:

{
    "pipeline": "yolov11s_gpu",
    "payload": {
        "source": {
            "uri": "file:///home/pipeline-server/videos/new_video_1_looped.mp4",
            "type": "uri"
        },
        "destination": {
            "metadata": {
                "type": "mqtt",
                "topic": "object_detection_$x",
                "publish_frame": false
            },
            "frame": {
                "type": "webrtc",
                "peer-id": "object_detection_$x"
            }
        },
        "parameters": {
            "detection-properties": {
                "model": "/home/pipeline-server/models/public/yolo11s/INT8/yolo11s.xml",
                "device": "GPU",
                "inference-interval": 3,
                "inference-region": 0,
                "batch-size": 8,
                "nireq": 2,
                "ie-config": "GPU_THROUGHPUT_STREAMS=2",
                "pre-process-backend": "va-surface-sharing",
                "threshold": 0.7
            },
            "classification-properties": {
                "model": "/home/pipeline-server/models/colorcls2/colorcls2.xml",
                "device": "GPU",
                "inference-interval": 3,
                "batch-size": 8,
                "nireq": 2,
                "ie-config": "GPU_THROUGHPUT_STREAMS=2",
                "pre-process-backend": "va-surface-sharing"
            }
        }
    }
}

Example: Running Stream Density Benchmark for Smart Parking#

This example will find the maximum number of smart parking streams that can run on the CPU while maintaining at least 15 FPS.

  1. Execute the benchmark_start.sh script, providing the desired pipeline name (yolov11s_gpu in this case). Here, we test a range of 1 to 16 streams.

    # Usage: ./benchmark_start.sh -p <pipeline_name> -l <lower_bound> -u <upper_bound> -t <target_fps>

./benchmark_start.sh -p yolov11s_gpu -l 1 -u 16 -t 15

  2. The script will output its progress as it tests different stream counts. The final output will show the optimal stream density found.

    ✅ FINAL RESULT: Stream-Density Benchmark Completed!
stream density: 8
======================================================

KPIs for the optimal configuration (8 streams):
throughput #1: 29.98
throughput #2: 29.98
...
throughput #8: 29.98
throughput median: 29.98
throughput average: 29.98
throughput stdev: 0
throughput cumulative: 239.84
throughput min: 29.98

Step 4: Stop the Benchmark#

After the benchmark is complete, or if you need to stop it manually, use the sample_stop.sh script. This will delete all running pipeline instances.

./sample_stop.sh