Why Not Deterministic?

Explore the reasons behind using randomness in lottery scheduling compared to deterministic stride scheduling. Learn how stride scheduling calculates exact resource shares and why lottery scheduling remains useful due to its simplicity and adaptability when new processes enter.

We'll cover the following...

- Stride scheduling
- Example

You might also be wondering: why use randomness at all? As we saw above, while randomness gets us a simple (and approximately correct) scheduler, it occasionally will not deliver the exact right proportions, especially over short time scales. For this reason, Waldspurger invented stride scheduling, a deterministic fair-share scheduler“Lottery and Stride Scheduling: Flexible Proportional-Share Resource Management” by Carl A. Waldspurger. Ph.D. Thesis, MIT, 1995. The award-winning thesis of Waldspurger’s that outlines lottery and stride scheduling. If you’re thinking of writing a Ph.D. dissertation at some point, you should always have a good example around, to give you something to strive for: this is such a good one..

Stride scheduling

Stride scheduling is also ...