Windows Internals, Fifth Edition

Thread Scheduling

This section describes the Windows scheduling policies and algorithms. The first subsection provides a condensed description of how scheduling works on Windows and a definition of key terms. Then Windows priority levels are described from both the Windows API and the Windows kernel points of view. After a review of the relevant Windows functions and Windows utilities and tools that relate to scheduling, the detailed data structures and algorithms that make up the Windows scheduling system are presented, with uniprocessor systems examined first and then multiprocessor systems.

Overview of Windows Scheduling

Windows implements a priority-driven, preemptive scheduling system—the highest-priority runnable (ready) thread always runs, ...