The Linux® kernel continues to evolve, incorporating new technologies and gaining in reliability, scalability, and performance. One of the most important features of the 2.6 kernel is a scheduler implemented by Ingo Molnar. This scheduler is dynamic, supports load-balancing, and operates in constant time -- O(1). This article explores these attributes of the Linux 2.6 scheduler, and more.
This article reviews the Linux 2.6 task scheduler and its most important attributes. But before diving into the details of the scheduler, let's understand a scheduler's basic goals.
What is a scheduler?
An operating system, in a general sense, mediates between applications and available resources. Some typical resources are memory and physical devices. But a CPU can also be considered a resource to which a scheduler can temporarily allocate a task (in quantities called slices of time). The scheduler makes it possible to execute multiple programs at the same time, thus sharing the CPU with users of varying needs.
An important goal of a scheduler is to allocate CPU time slices efficiently while providing a responsive user experience. The scheduler can also be faced with such conflicting goals as minimizing response times for critical real-time tasks while maximizing overall CPU utilization. Let's see how the Linux 2.6 scheduler accomplishes these goals, compared to earlier schedulers.
