System Duty Cycle scheduler class

Perhaps you’ve read about the System Duty Cycle scheduler class. Some people reported about it, but rather cursory. So … what is the story behind the System Duty Cycle scheduler or short SDC?
Before digging into the SDC, i should explain that the scheduler is a sophisticated little beast. You have several scheduling classes: The TS (time sharing) is the normal scheduling class, there is the IA (interactive) that prioritize the process that’s in focus in your desktop environment and it changes priorities based on some rules to ensure an even distribution of compute power for all the threads. You have the FX (fixed) scheduler, that keeps the priority fixed during the complete life time of the process. There is the FSS (fair share scheduler) that distributes the compute time on the system by introducing a concept called shares. A thread gets compute time on the basis of shares it owns. The kernel has a special scheduling class called SYS (system) and at last there is a scheduling class called RT (realtime). To understand the idea of the SDC you have to know a few things about the Solaris scheduling: