Performance evaluation of a software architecture for real-time call processing

Computers running under the UNIX operating system are used as adjunct processors to a switch to share call-processing responsibilities. In this architecture, call-processing tasks inside the adjunct processors are embedded in UNIX user processes. The author built a discrete-event driven, C-based, UNIX simulation model at a level of detail that allows one to obtain the statistics of many system task overheads. The model can give an accurate estimate of the system capacity by providing the breakdown of CPU time spent in context switches, I/O, IPC system calls, and user processes. In addition, the author found that the system can be trapped in a deadlock or “livelock” situation if not properly controlled. Causes and solutions to the deadlock/livelock condition were investigated