Following our previous posts (http://lists.ros.org/lurker/message/20140918.011916.e0e9cd9e.en.html and http://lists.ros.org/lurker/message/20140929.022230.7c75e176.en.html) , again we are posting some updates here in a separate thread.

We did some tests to demonstrate the effectiveness of the PREEMPT_RT patched Linux kernel, compared with the vanilla kernel coming with Ubuntu. To be more specific, jitters in ROS message communications (both topic- and service-based) upon the non-real-time and real-time kernels are recorded, while the source code of the test tries to maintain a fixed communication rate (10kHz in our case). The source code can be downloaded from:

And the results are shown in the charts below:

The test environment is described below:

OS: Ubuntu 12.04 32-bit

Vanilla kernel version: 3.8.0

Real-time kernel version: linux-3.8.13-rt16

ROS version: Groovy