Hi all,
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:
http://micros.nudt.edu.cn/ros/attachments/download/6440/ros_rt_test_src.tar.gz
And the results are shown in the charts below:
http://micros.nudt.edu.cn/ros/attachments/download/6435/topic_one_subscriber.pnghttp://micros.nudt.edu.cn/ros/attachments/download/6436/topic_two_subscriber.pnghttp://micros.nudt.edu.cn/ros/attachments/download/6437/topic_four_subscriber.pnghttp://micros.nudt.edu.cn/ros/attachments/download/6438/topic_eight_subscriber.pnghttp://micros.nudt.edu.cn/ros/attachments/download/6439/service.png
The test environment is described below:OS: Ubuntu 12.04 32-bitVanilla kernel version: 3.8.0Real-time kernel version: linux-3.8.13-rt16ROS version: Groovy
Best regards,Yanzhen
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%20,%20again%20we%20are%20posting%20some%20updates%20here%20in%20a%20separate%20thread.%0A>%20We%20did%20some%20tests%20to%20demonstrate%20the%20effectiveness%20of%20the%20PREEMPT_RT%20patched%20Linux%20kernel,%20compared%20with%20the%20vanilla%20kernel%20coming%20with%20Ubuntu.%20To%20be%20more%20specific,%20jitters%20in%20ROS%20message%20communications%20(both%20topic-%20and%20service-based)%20upon%20the%20non-real-time%20and%20real-time%20kernels%20are%20recorded,%20while%20the%20source%20code%20of%20the%20test%20tries%20to%20maintain%20a%20fixed%20communication%20rate%20(10kHz%20in%20our%20case).%20The%20source%20code%20can%20be%20downloaded%20from:http://micros.nudt.edu.cn/ros/attachments/download/6440/ros_rt_test_src.tar.gz%0A>%20And%20the%20results%20are%20shown%20in%20the%20charts%20below:http://micros.nudt.edu.cn/ros/attachments/download/6435/topic_one_subscriber.pnghttp://micros.nudt.edu.cn/ros/attachments/download/6436/topic_two_subscriber.pnghttp://micros.nudt.edu.cn/ros/attachments/download/6437/topic_four_subscriber.pnghttp://micros.nudt.edu.cn/ros/attachments/download/6438/topic_eight_subscriber.pnghttp://micros.nudt.edu.cn/ros/attachments/download/6439/service.png%0A>%20The%20test%20environment%20is%20described%20below:OS:%20Ubuntu%2012.04%2032-bitVanilla%20kernel%20version:%203.8.0Real-time%20kernel%20version:%20linux-3.8.13-rt16ROS%20version:%20Groovy%0A>%20Best%20regards,Yanzhen%0A>%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20%20_______________________________________________%0A>%20ros-users%20mailing%20list%0A>%20ros-users@lists.ros.org%0A>%20http://lists.ros.org/mailman/listinfo/ros-users%0A>%20 "Besvar denne besked")
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