ROS 2 Agnocast

True Zero Copy Communication Middleware for Undefined ROS 2 Message Types.

prototype: https://github.com/sykwer/agnocast

Build

Setup.

bash scripts/setup

Build.

colcon build --symlink-install --cmake-args -DCMAKE_BUILD_TYPE=Release

Run

Insert kernel module.

sudo modprobe agnocast

Run sample app (different window for each script). The order does not matter.

bash scripts/run_listener
bash scripts/run_talker

Stop applications and unload kernel module.

sudo modprobe -r agnocast

Debug

Check the kernel log.

sudo dmesg -w

To use dynamic_debug for dynamically outputting debug logs, please run the following command as super user:

sudo su
echo 'file agnocast_main.c +p' > /sys/kernel/debug/dynamic_debug/control

Check if dynamic_debug is enabled by running the following command. If the right side of the = is p, it is enabled. (If it’s _, it is disabled.)

sudo cat /sys/kernel/debug/dynamic_debug/control | grep "agnocast_main.c"
/.../agnocast/agnocast_kmod/agnocast_main.c:810 [agnocast]release_msgs_to_meet_depth =p "Release oldest message in the publisher_queue (publisher_pid=%d) of the topic (topic_name=%s) with qos_depth %d. (release_msgs_to_meet_depth)\012"
/.../agnocast/agnocast_kmod/agnocast_main.c:367 [agnocast]insert_message_entry =p "Insert an entry (topic_name=%s publisher_pid=%d msg_virtual_address=%lld timestamp=%lld). (insert_message_entry)"

To use dynamic_debug, the Linux kernel configuration must have CONFIG_DYNAMIC_DEBUG set to y. If CONFIG_DYNAMIC_DEBUG is not enabled in your environment, perform a debug build with:

make CFLAGS_agnocast.o="-DDEBUG"

Refer to the Linux kernel documentation on kbuild for more information about compilation flags.

Documents

• shared memory
• message queue
• Autoware integration
• Memory format in heaphook
• Clang-tidy Suppressions
• How to set environment variables
• ros2 command extension

Troubleshooting

Although Agnocast includes cleanup procedures for resources like shared memory and message queues, these resources may sometimes remain in the system. If you notice that available system memory decreases every time you run an Agnocast-enabled application, you’ll need to remove leftover shared memory objects by running:

rm /dev/shm/agnocast@*

Additionally, if you encounter the error mq_open failed: No space left on device, it means that the system has reached the maximum number of message queues. In that case, you may need to remove leftover message queues by running:

rm /dev/mqueue/agnocast@*
rm /dev/mqueue/agnocast_to_ros2@*

File truncated at 100 lines see the full file