I am just porting some real-time control software to qnx. I would like to use resource managers for interfacing the 
actual controller code with hardware-io (driver) code. However,  performance is very important for my application. 
That's why I'm wondering how using a resource manager compares with using other IPC methods (e.g. message queues) 
performance-wise. 
Typical read/write sizes would be only a few bytes, but there are several reads and writes every msec. I guess the 
question is, how high is the overhead of using the resource manager framework compared to native message passing?
Any help would be greatly appreciated.

Thomas