Abstract: In the context of battery-powered real-time systems, three
constraints need to be addressed: energy, deadlines and task rewards. Many
future real-time systems will count on different software versions, each with
different rewards, time and energy requirements, to achieve a variety of
QoS-aware tradeoffs. We first propose a solution that allows the device to run
the most valuable task versions while still meeting all deadlines and without
depleting a given energy budget. Assuming that the energy budget can be
replenished by using a rechargeable battery, we also propose (i) a static
solution that maximizes the system value assuming a worst-case scenario (i.e.,
worst-case battery recharging/discharging conditions, as well as worst-case
task execution times); and (ii) a dynamic scheme that takes advantage of the
extra energy in the system when worst-case scenarios do not happen. Three
dynamic policies are shown to make better use of the recharging energy while
improving the system value.