Adaptive Partitioning - Scheduler #

Aka APS

What is it?#

It's a fair-share thread scheduler which guarantees groups of a user-specified percentage of cpu time when the system is overloaded. When the system is sufficently underloaded, it chooses to schedule threads based strictly on priority and therefore maintians real-time behavior. Even when overloaded it provides real-time latencies to an engineerable set of critical threads.

Scheduler Partitioning is part of an overall resource partitioning strategy. See Adaptive Partitioning.

Table of Contents#

1. Presentation on APS
   • slide presentation: history / use cases / why is it "adaptive" / why is it cool
   • video commentary by the main perp to go with the slide presentation (comming real soon now)
2. QNX Designer's Documentation
   • Requirements Document: requirements / APIs / Limitations
   • How it works FAQ: Scheduling / Microbilling/ Algorithms / Overhead / Bankruptcy / Inheritance / Budgets / Security
3. Hacking
   • Where to find the source code.
   • How to build APS
   • APS_Buildfile_extensions
4. Links to user's documents:
   • Adapative Partitionig User's Guide
   • Installation Notes
   • Release Notes
   • APS Command Reference
   • Library reference for SchedCtl()
   • APS chapter from the QNX System Architecture guide.