Why is Cyclone the default DDS and not Fast DDS?

[antopost]

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Why is Cyclone the default for Autoware and not Fast DDS?

At some point the developers decided to make Cyclone the default backend.
Since Fast DDS is the ROS2 default this can only have been a conscious and deliberate decision.

But when comparing the two, I don't really understand what Cyclone's advantage is over Fast DDS.
Both are similar in performance according to this technical report with Fast DDS maybe having the slight upper hand. Mind that the developers conducted the report, so it's not unbiased.
But one feature that clearly makes Fast DDS a stronger candidate is its statistics backend which makes monitoring a lot easier. I couldn't find any equivalent for Cyclone.

[mitsudome-r]

It's just that we have made our DDS configurations for Autoware when Cyclone DDS was the default DDS back in ROS Galactic.

Usually, one would have to configure DDS settings to make DDS work stably especially if you are working with large topics and communication across multiple machines. If we can find a good configuration for Fast DDS that works out of the box, then we could consider making Fast DDS default DDS as well.