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

[Sean Anderson]

CPU looks like 30%

load average machine 1 (quad core)
load average: 1.24, 1.58, 1.44

load average machine2 (dual core)
load average: 0.06, 0.03, 0.01

i used iostat to look at what I believe is hard drive io, and the
utilization is almost always 0%, spikes at 8%

is there some other io you were looking for?

On Mon, Mar 7, 2011 at 7:13 PM, Tully Foote <tfoote at willowgarage.com> wrote:

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