RTEMS: Adding a new scheduler

In this post I describe how to add a new scheduler implementation to the RTEMS open-source real-time operating system. The scheduler I use as an example is an earliest deadline first (EDF) scheduler which applies the EDF algorithm to schedule periodic tasks and a FIFO policy for non-periodic tasks.  This post demonstrates how to use my modular scheduling framework to extend the scheduling capabilities of RTEMS.

Architectural simulators

As a researcher in the areas of operating systems, compilers, and computer architecture, I spend a lot of time dealing with simulators.  An inordinate amount of time.  Much of this time is spent figuring out how well a given simulator provides:

1. Useful timing measurements (cycle-accurate)
2. Support for fully functional OSs (full-system)
3. Auxiliary features for specific experiments
4. Support for useful hardware platforms and instruction sets
5. Openness to modifying microarchitectural features
6. Availability of technical support

In my current work, I'm interested in actively developed simulators that support cycle-accurate full-system simulation with a detailed memory hierarchy on out-of-order uniprocessor or multicore RISC architecture models with the SPARC, MIPS, or ARM instruction sets that supports extending the pipeline and instruction set.  The rest of this article discussed my efforts in finding simulators to meet my needs.