Scheduling algorithm used in Windows 7

Question

What is the scheduling algorithm used in Windows 7?

Solution 1

Windows uses a round-robin technique with a multi-level feedback queue for priority scheduling ever since NT, Though in Vista there were some smart heuristic improvements to ensure that some processes, such as the disk defragmenter, are at a lower priority in order to not interfer with foreground processes. To the best of my knowledge, Windows 7 uses the same scheduler as Vista, though there may have been minor improvements.

Solution 2

Windows NT-based operating systems use a multilevel feedback queue. So, I feel that Windows 7 must also be using the same scheduling algorithm.
The scheduler was modified in Windows Vista with the inclusion of a priority scheduler and also to use the cycle counter register of modern processors to keep track of exactly how many CPU cycles a thread has executed.
On similar lines, there may be some improvements in Windows 7 too. But the algorithm may be the same.

Comments

[David Schwartz]

This is an extremely vague and open-ended question. What do you want to know?

[arulappan]

Many scheduling algorithms like First come first serve, Priority based, Round Robin are there. Is there any specific algorithm is used in that OS?

[David Schwartz]

It is a multilevel feedback queue with some modifications.

[akira]

@arulappan: scheduling algorithm for what kind of items?

[arulappan]

@akira: To schedule tasks for the processor in 'Multitasking' environment.

[akira]

@arulappan: put that into your question.

[David Schwartz]

What makes you think this question was about UMS?

[Richard]

For details – to the extent they have been published – see Windows Internals by Mark Russinovich et al.