Scheduling
The second big topic I want to cover in this chapter is scheduling. The Linux scheduler has a queue of threads that are ready to run and its job is to schedule them on CPUs as they become available. Each thread has a scheduling policy which may be timeshared or real-time. The timeshared threads have a niceness value which increases or reduces their entitlement to CPU time. The real-time threads have a priority such that a higher priority thread will preempt a lower one. The scheduler works with threads, not processes. Each thread is scheduled regardless of which process it is running in.
The scheduler runs when:
- A thread blocks by calling
sleep()or in a blocking I/O call - A timeshare thread exhausts its time slice
- An interrupt causes a ...
Get Mastering Embedded Linux Programming now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
