Bad performance with kinematic body

[finscn]

I create a demo 'Tumbler' for testing performance .

And I found a strange thing.

When I use kinematic body to the Tumbler outbox , the performance is bad.
http://fatidol.com/phy-benchmark/box2d-ts-test.html?type=kinematic
(40 FPS on my macbook)

When I use dynamic body + revolute joint to the Tumbler outbox , the performance is better.
http://fatidol.com/phy-benchmark/box2d-ts-test.html
(60 FPS on my macbook)

This result puzzles me :
When & How should I use kinematic ?

[Nek-]

This experiment is interesting. I hope you don't mind I created a gist with the code as record in case your site is down :) .

https://gist.github.com/Nek-/d48853f93c8bde0592c92bab3da6af96

[flyover]

@finscn Have you tried this on the C++ version? It sounds like it might not be specific to this port.

[finscn]

I don't any thing about C++ . So I'm sorry I can't give any help