CACHE-INDUCED EXECUTION TIME VARIABILITY OF SATELLITE ON-BOARD SOFTWARE IN A LEON-2 MICROPROCESSOR

摘要

As a source of indeterminism, the cache subsystem ofthe LEON processor makes the schedulability analysisof spacecrafts’ OBSW still more complicated. Inparticular, it is not easy to formally assess the impactupon the global worst-case execution time (WCET) ofminor modifications and/or alternatives in the softwarecontrol flow. In multi-tasking, real-time applications(like the control SW of spacecraft subsystems) thefrequent context-switches between tasks make thisproblem especially difficult. The objective of this studyis to empirically assess the degree of cache-inducedexecution time variability we can find in an existing,complex, real-time software running on a LEON-2processor.