[ros-users] Generic message transport infrastructure

[Konrad Banachowicz]

I don't think that shm is right way of communication for ROS.
It is extremely low-level approach to the problem and it's possibly
duplicate existing in system messaging like UNIX domain socket or POSIQ MQ.
Additional overhead for providing reliable communication would be difficult
to achieve and would have significant impact on performance.

In my opinion using UNIX domain socket would be much more beneficial to ROS
and much simpler to implement.

Pozdrawiam
Konrad Banachowicz


2010/12/3 Josh Faust <jfaust at willowgarage.com>

> I don't think common use will likely crash it: e.g. images and point cloud
>> are not always changing size. And the nodes should not crash if the object
>> size stays constant.
>>
>
> Common use for a "generic message transport" is more than just fixed-size
> images and point clouds (and point clouds often change size, at least if
> they're from something like a stereo camera).  There is nothing in the
> documentation stating that the shared memory plugin will only work in this
> one very specific use case, and if you use it for anything else you may get
> invalid data (like, say, half one image and half another, or two of the same
> image in a row) or cause a crash.
>
> In fact, even in the case of a fixed size image it can cause a crash, since
> the publisher deletes its shared memory when it destructs, meaning any
> subscriber that hasn't already processed all of its messages will crash.
>
> Josh
>
> _______________________________________________
> ros-users mailing list
> ros-users at code.ros.org
> https://code.ros.org/mailman/listinfo/ros-users
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.ros.org/pipermail/ros-users/attachments/20101203/6c39da02/attachment-0003.html>