basic_topic_sub_pub.md

How To Run Basic Topic Subscription Publishing Benchmark

Firstly, source your ros version. It's suggested to test with rolling version of ROS 2.

For instance, to test with rmw_zenoh, start to zenoh router using following command in the terminal.

# go to your workspace
cd ws
# Be sure that ros2 daemon is killed.
pkill -9 -f ros && ros2 daemon stop
# Then start zenoh router
source /opt/ros/rolling/setup.bash
source install/setup.bash
export RMW_IMPLEMENTATION=rmw_zenoh_cpp
ros2 run rmw_zenoh_cpp rmw_zenohd

Select your rmw_implementation as rmw_zenoh_cpp and run the perception benchmark launch file in the another terminal.

# go to your workspace
cd ws
source /opt/ros/rolling/setup.bash
source install/setup.bash
export RMW_IMPLEMENTATION=rmw_zenoh_cpp # select your rmw_implementation to benchmark
ros2 launch moveit_middleware_benchmark scenario_basic_subscription_benchmark.launch.py

It will be defaultly benchmarked with 6 repetitions. It will be created the json file named middleware_benchmark_results.json for benchmarking results after finishing benchmark code execution. You can see the benchmark results in more detail inside this json file.

If you want to customize your benchmark arguments or select different test case, you can use below command.

ros2 launch moveit_middleware_benchmark scenario_basic_subscription_benchmark.launch.py benchmark_command_args:="--benchmark_out=middleware_benchmark_results.json --benchmark_out_format=json --benchmark_repetitions=1" pose_array_size:=1000 benchmarked_topic_name:="/dummy_benchmark_topic_name" benchmarked_topic_hz:=10 max_received_topic_number:=100

Let's explain some parameters used in benchmark.

args	explanation
benchmark_command_args	you can utilize this parameter to use custom benchmark arguments in your benchmark
pose_array_size	In this benchmark, geometry_msgs/msg/PoseArray is used. This parameter presents how many poses will be published from basic_topic_publisher. You can set message size sent by basic_topic_publisher using this parameter.
benchmarked_topic_hz	This parameter presents in how many rate the message will be published from basic_topic_publisher.
max_received_message_number	This parameter sets how many message to handled by scenario_basic_subscription benchmarking module. The more message number is handled, the more reliable benchmark results is achieved in scenario_basic_subscription scenario.

How to benchmark the basic topic subscription publishing works

The main idea here is to firstly save the message timestamp when published from basic_topic_publisher and then handle this message in scenario_basic_subscription benchmarking module by which this message is received. This benchmark module uses geometry_msgs/msg/PoseArray which has arrangeable size and timestamp sections in message body. When message is received by scenario_basic_subscription benchmarking module, the difference between the time message is received and the time message is sent is added to total elapsed time. In the end, this total elapsed time is saved to benchmark results.