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Recording with CARET#

This page explains usage of CARET with a sample application. The sample application is located on CARET_demos repository.

See Recording to find more details.

Building application with CARET#

To trace a target application, the target should be built with CARET/rclcpp. If you have already built the target without CARET/rclcpp, you have to build the target with CARET/rclcpp again. For building the application with CARET/rclcpp, CARET's local_setup.bash should be applied along with ROS 2's setup.bash as shown below.

mkdir -p ~/ros2_ws/src
cd ~/ros2_ws

git clone src/CARET_demos

source /opt/ros/humble/setup.bash
source ~/ros2_caret_ws/install/local_setup.bash # please keep the order after 'source /opt/ros/humble/setup.bash'

colcon build --symlink-install --packages-up-to caret_demos --cmake-args -DBUILD_TESTING=OFF

The following command allows you to check whether CARET/rclcpp is applied to each package. If caret/rclcpp is not applied to the package you want to record, please check which rclcpp is used for the target and your workspace's environment variables.

ros2 caret check_caret_rclcpp --workspace ~/ros2_ws/

# Expected output. CARET/rclcpp is applied to all packages
INFO    : 2022-06-12 12:26:49 | All packages are built using caret-rclcpp.

# In case there are packages to which CARET/rclcpp is not applied
# The following message will be outputted
WARNING : 2022-06-12 12:25:26 | The following packages have not been built using caret-rclcpp:

Tracing the sample application with CARET#

Launching the target application#

Run the target as shown in the following.

# Environment settings (keep the order as below)
source /opt/ros/humble/setup.bash
source ~/ros2_caret_ws/install/local_setup.bash
source ~/ros2_ws/install/local_setup.bash

# Enable tracepoints which are defined hooked functions.
export LD_PRELOAD=$(readlink -f ~/ros2_caret_ws/install/caret_trace/lib/

# (Optional) Exclude nodes and topics which you are not concerned with
export CARET_IGNORE_NODES="/rviz*"
export CARET_IGNORE_TOPICS="/clock:/parameter_events"

# Launch the target application, demos_end_to_end_sample
ros2 launch caret_demos

Starting recording#

Open a new terminal and record the performance data.

source /opt/ros/humble/setup.bash
source ~/ros2_caret_ws/install/local_setup.bash

# set a destination directory. ~/.ros/tracing is default.
mkdir -p ~/ros2_ws/evaluate
export ROS_TRACE_DIR=~/ros2_ws/evaluate

ros2 caret record -s e2e_sample

# Start recording with pressing Enter key
# > All process tarted recording.
# > press enter to stop...

Validating recorded data briefly#

You can check whether tracing is successful or not with ros2 caret check_ctf command before visualizing recorded data.

ros2 caret check_ctf -d ~/ros2_ws/evaluate/e2e_sample/

# If there are problems with the recorded data, warning messages will be displayed.