Investigation of Scratchpad Memory for Preemptive Multitasking

Jack Whitham, Robert I Davis, Neil C Audsley, Sebastian Altmeyer, Claire Maiza

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We present a multitasking scratchpad memory reuse scheme (MSRS) for the dynamic partitioning of scratchpad memory between tasks in a preemptive multitasking system. We specify a means to compute the worst-case response time (WCRT) and schedulability of task sets executed using MSRS. Our scratchpad-related preemption delay (SRPD) is an analog of cache-related preemption delay (CRPD), proposed in previous work as a way to compute the worst-case cost imposed upon a preempted task by preemption in a multitasking system. Unlike CRPD, however, SRPD is independent of the number of tasks and the local memory size. We compare SRPD with CRPD by experiment and determine that neither dominates the other, i.e. either may be better for certain task sets. However, MSRS leads to improved schedulability versus cache when contention for local memory space is high, either because the local memory size is small, or because the task set is large, provided that the cost of loading blocks from external memory to scratchpad is similar to the cost of loading blocks into cache.
Original languageEnglish
Title of host publicationReal-Time Systems Symposium (RTSS), 2012 IEEE 33rd
ISBN (Print)9781467330985
Publication statusPublished - Dec 2012
EventReal-Time Systems Symposium (RTSS), 2012 IEEE 33rd - San Juan , Puerto Rico
Duration: 4 Dec 20127 Dec 2012


ConferenceReal-Time Systems Symposium (RTSS), 2012 IEEE 33rd
Country/TerritoryPuerto Rico
CitySan Juan

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