Ken,
The paper you pointed to was using Box Turtle and found that performance of
ROS wss pretty good compared to (what appears to be very optimised) LCM.
Do you think C-turtle got any improvements in this area?
>From paper:
>The ROS TCP transport achieves high throughput when the maximum queue
length (q) is set to infinity, but at the
>expense of message latency. Various settings of q provide an adjustable
tradeoff between throughput and latency.
On Thu, Sep 9, 2010 at 12:06 PM, Ken Conley <
kwc@willowgarage.com> wrote:
> Hi Konrad,
>
> If you read this paper from the authors of LCM, you will find that the
> performance of ROS, LCM, and IPC are generally comparable (note: the
> article tests LCM's UDP implementation against ROS' TCP
> implementation):
>
> http://lcm.googlecode.com/files/2010-huang-olson-moore-lcm-iros.pdf
>
> Comparing any middleware to "raw TCP" is generally difficult to come
> to conclusions, especially without including exact information on how
> your test was conducted. With any middleware, there is the overhead of
> (un)marshaling the data into individual messages. The size and
> composition of these messages is a significant factor in any
> performance numbers that result.
>
> - Ken
>
> On Thu, Sep 9, 2010 at 11:48 AM, Konrad Banachowicz <konradb3@gmail.com>
> wrote:
> > Dear all,
> > I recently done some testing on ROS communication performence.
> > There are the reesults :
> > throughput [MB/s] time [s] data
> [MB]
> > ROS 7.25906 4.827058 35.0399
> > raw TCP 56.8430 8.387205 476.75466
> > POSIX MQ 124.36626 3.834136 476.837158
> >
> > That shows grate overhead of ROS communication.
> > I looked on code, I found that the communication code is very complicated
> > and contains many locks and queues. It's also integrate interprocess and
> > intraprocess communication. This with all callback stuff make whole
> > communication overcomplicated.
> >
> > I think this show serious problem with design of whole network stack in
> ROS.
> >
> > I will do some more testing.
> >
> > Pozdrawiam
> > Konrad Banachowicz
> >
> > _______________________________________________
> > ros-users mailing list
> > ros-users@code.ros.org
> > https://code.ros.org/mailman/listinfo/ros-users
> >
> >
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