subscribe the sensor data not in real time

[BoWangFromMars]

When I used iiwa_stack, something confused me. For example, when I subscribed the sensor data via rostopic '/iiwa/state/JointPosition' and '/iiwa/state/JointTorque' from iiwa robot, I got discontinous data(please see the following figure, which shows iiwa/state/JointPosition recorded by rosbag).

For this issue, I tried to figure it out and got a possible reason, that is because iiwa_stack was based on KUKA Sunrise.Servoing package, which was only a soft real-time interface(please see it at https://www.kuka.com/en-de/products/robot-systems/software/system-software/sunriseos).

I asked someone else who also used iiwa_stack, but they did not meet the problem as mine. Then, I restarted to check the difference of configuration between mine and the author's. I find some clues. For the question 'Which version of Sunrise.OS/Sunrise Workbench is supported?' says that the stack relies on Connectivity/Servoing package. Could you please tell me what the Connectivity package is and how can I check whether my Sunrise workbench has it or not? Further, the Connectivity package affects the iiwa robot communicating with ROS machine in real time?