Comparison of Context Switching Methods for Fine Grain Process Scheduling

Context switching times are a major source of overhead in medium to fine grain process scheduling. We compared three different context switching techniques for non-preemptive scheduling in context of hardware/software codesign, and found major differences in performance and code size efficiency. 1 Introduction The impact of context switching on the overall execution time of a real--time system depends on the hardware platform and on the type of constraints. While in the design of larger real-time systems, context switching time is often neglected or roughly estimated or bounded [2, 10], this is less useful in hardware/software system design with many different communication mechanisms and tasks which can have widely varying time constraints. Typical real-time operating systems show context switching times of several to tens of microseconds [2] which is large compared to hardware/software communication or hardware execution times. So, in trading off hardware and software solutions, a c..