Difference between the Windows and Linux thread scheduler

The difference between the Windows and Linux thread scheduler is one of the more commonly asked questions for IT administrators. This article aims to provide an overview of the differences between the two operating systems in terms of thread scheduling.

Windows thread scheduler

The Windows thread scheduler is a preemptive, priority-based round-robin scheduler that is used to assign a priority to each thread in the system. This scheduler assigns a priority to each thread based on the thread's priority class and the number of threads waiting to be scheduled. The higher the priority class and the more threads waiting to be scheduled, the higher the priority assigned to the thread.

The Windows thread scheduler uses a preemptive scheduling algorithm to determine which thread should be scheduled next. This means that a thread can be preempted if a higher priority thread is ready to be scheduled. This ensures that higher priority threads are scheduled first and lower priority threads are only scheduled when no higher priority threads are available.

Linux thread scheduler

The Linux thread scheduler is a preemptive, time-slice based scheduler. This means that each thread is assigned a time-slice in which it can run, and once the time-slice has expired the thread is preempted and the next thread is scheduled.

The Linux thread scheduler also uses priority-based scheduling. However, the priority is assigned dynamically and is based on the amount of time the thread has spent waiting and the priority of the thread's parent process. This means that a thread's priority can change over time depending on how much time it has spent waiting and how important its parent process is.

The Linux thread scheduler also uses a fairness algorithm to ensure that threads are not starved for resources. This means that if a thread has been waiting for a long time and has not been scheduled, the scheduler will assign it a higher priority so that it gets the resources it needs.

Conclusion

The Windows and Linux thread schedulers are both preemptive, priority-based schedulers. However, they differ in terms of how they assign priorities and the algorithms they use to ensure fairness. Windows uses a static, priority-based system while Linux uses a dynamic, time-slice based system. Additionally, the Linux scheduler uses a fairness algorithm to ensure that threads are not starved for resources.