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Bad performance of ROS2 via Wifi

asked 2020-09-22 05:29:53 -0500

NEngelhard gravatar image

I have a simple setup with a laptop on a mobile robot (Foxy) from which I only want to stream data from a laserscanner to a stationary computer that has a wifi dongle. If I only open the scanner on the laptop, I get around 30Hz but If I also subscribe on the workstation, this frequency drops to 20Hz (on the laptop!) and I only get 2-3 Hz on the workstation (always a small burst of messages every 5 seconds).

Streaming a laser scanner really shouldn't be an issue and a slow or unreliable connection to a new subscriber shouldn't decrease the local performance. Reliability is on Best_effort, Durability Volatile.

I'm using the default DDS, are there any settings I have to change?

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Possibly related: ROS2 Default Behavior (Wifi).

I've seen suggestions to use Cyclone DDS, but also reports that newer versions of FastRTPS should fix this.

gvdhoorn gravatar image gvdhoorn  ( 2020-09-22 05:57:25 -0500 )edit

If you have time I would appreciate it if you reported your experience in our Foxy RMW survey.

kscottz gravatar image kscottz  ( 2020-09-22 13:05:00 -0500 )edit

I have this same problem and just tried Cyclone DDS, but it shows the same results. What bothers me most is that the local rate on the computer on the mobile robot also decreases. This makes monitoring using rviz kind of risky, because it lowers the rate at which control happens on the mobile robot...

Mbuijs gravatar image Mbuijs  ( 2020-09-23 03:54:17 -0500 )edit

I would suggest to post a comment on the Discourse thread (in addition to the survey @kscottz linked), as that is currently the central place for these types of reports to get noticed.

gvdhoorn gravatar image gvdhoorn  ( 2020-09-23 03:57:27 -0500 )edit

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answered 2020-09-23 10:02:56 -0500

NEngelhard gravatar image

I ran some experiments and I think the problem was the Wifi-Dongle on the workstation. I moved the Laptop into a different wifi that is connected to the Lan and after that, the workstation received all sensor data flawlessly.

But that still does not explain why the performance degraded on the Laptop as soon as a subscriber over wifi was started.

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https://en.wikipedia.org/wiki/Hidden_...

It's quite easy for the WIFI later to collapse if you start to pump data down it. There lots of things you can do to optomise WIFI, however the less things you have on WIFI the better... how much data are you pumping over WIFI?

l33 gravatar image l33  ( 2020-10-03 13:36:31 -0500 )edit

I only have the laser data on the wifi, which is around 500kB/s

NEngelhard gravatar image NEngelhard  ( 2020-10-06 09:54:16 -0500 )edit

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Asked: 2020-09-22 05:29:53 -0500

Seen: 65 times

Last updated: Sep 23