Multiple-Processor Scheduling

5.5 Multiple-Processor Scheduling

When multiple processors are available, then the scheduling gets more complicated, because now there is more than one CPU which must be kept busy and in effective use at all times

Multi-processor systems may be heterogeneous, ( different kinds of CPUs ), or homogenous, ( all the same kind of CPU )


One approach to multi-processor scheduling is asymmetric multiprocessing, in which one processor is the master, controlling all activities and running all kernel code, while the other runs only user code. This approach is relatively simple, as there is no need to share critical system data.

Another approach is symmetric multiprocessing, SMP, where each processor schedules its own jobs, either from a common ready queue or from separate ready queues for each processor.
Virtually all modern OSes support SMP, including XP, Win 2000, Solaris, Linux, and Mac OSX.

www2.cs.uic.edu/~jbell/CourseNotes/OperatingSystems/5_CPU_Scheduling.html