Explaining the GNU Radio Scheduler

The most important and distinguishing piece of GNU Radio is the underlying scheduler and framework for implementing and connecting the signal processing blocks. While there are many other libraries of DSP blocks available, it's GNU Radio's scheduler that provides a common, fast, and robust platform to research, develop, and share new ideas. On the other hand, the scheduler is the most mysterious and complicated part of the GNU Radio code base. We often warn when people start talking about modifying the scheduler that, to use the cliche, "There be dragons!" Since the scheduler is so complicated and any change (and therefore bug) introduced to it will affect everything else, we have to be careful with what we do inside of it.

Still, we may want to add new features, improvements, or changes to the scheduler, and do to so, we need to understand the entire scheduler to make sure that our changes fit and don't cause problems elsewhere. The scheduler has a number of responsibilities, and within each responsibility, there are checks, balances, and performance issues to consider. But we've never really documented the code, and only a few people have gone in and really analyzed and understood the scheduler. So I've gone about creating this presentation to try to break down the scheduler into its pieces to help improve the overall understanding of what goes on inside. Hopefully, this will demystify it to some extent.

Overview of the GNU Radio Scheduler