[ros-users] Is ROS limiting channel bandwidth over network?

Tully Foote tfoote at willowgarage.com
Tue Mar 8 00:13:20 UTC 2011


What does your CPU, load average, other IO load look like on both machines?
It could be limited by the compression instead of the throughput.

Tully

On Mon, Mar 7, 2011 at 2:52 PM, Sean Anderson <
sean.william.anderson at gmail.com> wrote:

> We've been watching on the system monitor of both machines
>
> We just subscribed to the raw channels instead of the compressed and we're
> seeing a transfer rate of up to 8MB/s on the system monitor instead of
> 1MB/s, so the problem has something to do with the compression
>
> any ideas?
>
>
> On Mon, Mar 7, 2011 at 5:27 PM, Ken Conley <kwc at willowgarage.com> wrote:
>
>> Have you taken the measurement using some other means?  Please note from
>> the documentation below that "rostopic bw" is not the best means of
>> measuring this:
>>
>> """
>> http://www.ros.org/wiki/rostopic#rostopic_bw
>> NOTE: the bandwidth reported is the received bandwidth. If there are
>> network connectivity issues, or if rostopic cannot keep up with the
>> publisher, the reported number may be lower than the actual bandwidth.
>> rostopic is implemented in Python, which cannot maintain as high throughput
>> as roscpp <http://www.ros.org/wiki/roscpp>-based nodes.
>> """
>>
>>  - Ken
>>
>> On Mon, Mar 7, 2011 at 2:21 PM, Sean Anderson <
>> sean.william.anderson at gmail.com> wrote:
>>
>>> Hi,
>>>
>>> My team is trying to use image_transport compression in order to transfer
>>> large amounts of image data over our wireless network.
>>>
>>> We're using wireless N, but we have been unable to transfer for than 1
>>> megabyte per sec over the network using ROS.
>>>
>>> When using "rostopic bw <channel>" in conjunction we have noticed that
>>> the bandwidth rises to 2 megabyte per sec (we've seen a max of 4MB/s with
>>> multiple tabs running the bw check)
>>>
>>> A colleague of mine noticed something about wpa_supplicant_node having a
>>> wireless 11b max bandwidth limiter, is this what is limiting our transfer
>>> rate? Does anyone know how to unlock the limit?
>>>
>>> Thanks so much,
>>>
>>> Sean Anderson
>>>
>>> _______________________________________________
>>> ros-users mailing list
>>> ros-users at code.ros.org
>>> https://code.ros.org/mailman/listinfo/ros-users
>>>
>>>
>>
>
> _______________________________________________
> ros-users mailing list
> ros-users at code.ros.org
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>
>


-- 
Tully Foote
Systems Engineer
Willow Garage, Inc.
tfoote at willowgarage.com
(650) 475-2827
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