71 lines
3.5 KiB
Markdown
71 lines
3.5 KiB
Markdown
# ROS2 RMW for Eclipse Cyclone DDS
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**Easy, fast, reliable, small [Eclipse Cyclone DDS](https://github.com/eclipse-cyclonedds/cyclonedds) middleware** for ROS2. Make your **🐢 run like a 🚀** [Eclipse Cyclone DDS has great adopters](https://iot.eclipse.org/adopters/) and contributors in the ROS community and is an [Eclipse Foundation](https://www.eclipse.org) open source project of [Eclipse IoT](https://iot.eclipse.org) and [OpenADx](https://openadx.eclipse.org) (autonomous driving).
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This package lets [*ROS2*](https://index.ros.org/doc/ros2) use [*Eclipse Cyclone DDS*](https://github.com/eclipse-cyclonedds/cyclonedds) as the underlying DDS implementation.
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Cyclone DDS is ready to use. It seeks to give the fastest, easiest, and most robust ROS2 experience. Let the Cyclone blow you away!
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1. Install:
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```
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apt install ros-eloquent-rmw-cyclonedds-cpp
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```
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or
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```
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apt install ros-dashing-rmw-cyclonedds-cpp
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```
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2. Set env variable and run ROS2 apps as usual:
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```export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp```
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3. Confirm RMW: In Eloquent and later, to confirm which RMW you're using:
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```ros2 doctor --report```
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## Performance recommendations
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With large samples (100s of kilobytes), excessive latency can be caused by running out of space in the OS-level receive buffer. For this reason, on Linux, we recommend increasing the buffer size:
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* Temporarily (until reboot): `sudo sysctl -w net.core.rmem_max=8388608 net.core.rmem_default=8388608`
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* Permanently: `echo "net.core.rmem_max=8388608\nnet.core.rmem_default=8388608\n" | sudo tee /etc/sysctl.d/60-cyclonedds.conf`
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## Debugging
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So Cyclone isn't playing nice or not giving you the performance you had hoped for? That's not good... Please [file an issue against this repository](https://github.com/ros2/rmw_cyclonedds/issues/new)!
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The `ddsperf` tool distributed with Cyclone DDS can be used to check that communication works *without* ROS. Run `ddsperf sanity` on two different machines - if the "mean" value is above `100000us`, there are likely network issues.
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If you're having trouble with nodes discovering others or can't use multicast *at all* on your network setup, you can circumvent discovery:
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`export CYCLONEDDS_URI='<Discovery><Peers><Peer Address='myroshost.local' /><Peer Address='myroshost2.local' /></></>'`
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Here are some ways to generate additional debugging info that can help identify the problem faster, and are helpful on an issue ticket:
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* Configure Cyclone to create richer debugging output:
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* To see the output live:
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`export CYCLONEDDS_URI='<Tracing><Verbosity>trace</><Out>stderr</></>'`
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* To send to `/var/log/`:
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`export CYCLONEDDS_URI='<Tracing><Verbosity>trace</><Out>/var/log/cyclonedds.${CYCLONEDDS_PID}.log</></>'`
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* Create a Wireshark capture:
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`wireshark -k -w wireshark.pcap.gz`
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## Building from source and contributing
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The following branches are actively maintained:
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* `master`, which targets the upcoming ROS version, [*Foxy*](https://index.ros.org/doc/ros2/Releases/Release-Foxy-Fitzroy/).
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* `dashing-eloquent`, which maintains compatibility with ROS releases [*Dashing*](https://index.ros.org/doc/ros2/Releases/Release-Dashing-Diademata/) and [*Eloquent*](https://index.ros.org/doc/ros2/Releases/Release-Eloquent-Elusor/)
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If building ROS2 from source ([ros2.repos](https://github.com/ros2/ros2/blob/master/ros2.repos)), you already have this package and Cyclone DDS:
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cd /opt/ros/master
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rosdep install --from src -i
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colcon build
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export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp
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