Publisher Subscriber Teleoperation -- High Latency?

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Is this latency on the same machine? If not, I'd check your network latency first with pings. ROS can't do anything to reduce network latency.

If it's all on the same machine. The next step would be to profile the code to see where the slow down is using either valgrind's callgrind or perhaps sysprof

Also, if you need to make sure that the ROS processes are guaranteed CPU time, and not affected by other process you should probably look into a realtime processing library like Xenomi along with rosrt. ROSRT can also slightly improve performance by avoiding memory allocations by preallocating. Those speed-ups should probably be helpful even if not running a real time system if small margins are important.