Like any time-sharing system, Linux achieves the magical effect of an apparent simultaneous execution of multiple processes by switching from one process to another in a very short time frame. Process switching itself was discussed in Chapter 3; this chapter deals with scheduling, which is concerned with when to switch and which process to choose.
The chapter consists of three parts. Section 11.1 introduces the choices made by Linux to schedule processes in the abstract. Section 11.2 discusses the data structures used to implement scheduling and the corresponding algorithm. Finally, Section 11.3 describes the system calls that affect process scheduling.