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Is topic communcation zero-copy if running multiple nodelets standalone? (instead of a manager)

asked 2017-04-20 08:08:37 -0500

takahashi gravatar image

updated 2017-04-20 08:15:02 -0500

I am confused by the Nodelet Docs regarding the two possibilities to run a nodelet (1.4 Basic Usage). Apparently, one can either

  • launch one nodelet manager and load multiple nodelets into this manager or
  • launch multiple standalone nodelets in different nodes.

    Is the communication between nodelets still zero-copy, if I launch them as standalone nodelets?

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answered 2017-04-20 12:03:35 -0500

Wolf gravatar image

updated 2017-04-20 13:27:34 -0500

No, the Data will be copied in this case. Zero copy publish/subscribe ist only possible if both nodelets Run in the Same process, i.e. in one node...

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thanks for the answer. but what is the purpose then of standalone nodelets? as far as I understood, the big advantage of nodelets over nodes is the zero-copy transport..

takahashi gravatar image takahashi  ( 2017-04-21 01:54:19 -0500 )edit

The advantage of standalone nodelets, is that you program the nodelet but can still run your module as a node. This maybe interesting for debugging porpuses...

You only get the zero-copy transport capability when the nodelets are started on the same nodelet_manager process.

jespestana gravatar image jespestana  ( 2019-02-13 03:37:57 -0500 )edit

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Asked: 2017-04-20 08:08:37 -0500

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Last updated: Apr 20 '17