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Time jumped forward

asked 2011-03-03 21:21:10 -0500

Hi folks,

I am receiving some error messages from everything that uses planning_environment (OMPL, Trajectory Filter, you name it!), namely that the joint_states messages are discarded and I should turn DEBUG on. When I look at the DEBUG messages, I see a dominant "Time jumped forward by xxx for timer of period [0.010000], resetting timer". Although I don't think that that is the problem, I was curious about this message. What does it mean? Is it bad?

BTW I am currently distributing the nodes among at least 3 computers. Although they query a local ntp server every minute, keeping them in sync is a big problem. How influential is this on the tf synchronisation problems?

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answered 2011-03-03 22:12:04 -0500

If synchronization between different contributing machines is off, this can generally cause a lot of problems with tf. The recommendation is to use chrony (http://chrony.tuxfamily.org/) instead of plain ntp for synchronization, as it is much more reliable.

There are quite a few posts on the mailing list about details: http://ros-users.122217.n3.nabble.com/template/NamlServlet.jtp?macro=search_page&node=122217&query=chrony

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Asked: 2011-03-03 21:21:10 -0500

Seen: 1,024 times

Last updated: Mar 03 '11