Section: New Results
Uniprocessor Real-Time Scheduling
Participants : Mehdi Mezouak, Yves Sorel, Walid Talaboulma.
In the context of the master internship of Mehdi Mezouak, we thoroughly tested
the offline time triggered scheduler implemented on an ARM Cortex M4 last
year. We remind that this scheduler, intended for safety critical applications,
uses a scheduling table containing the instants when the scheduler will be
called through interruptions triggered by a timer. This table is generated by a
uniprocessor offline schedulability analysis which accounts accurately for the scheduler cost itself, and for the cost of all
preemptions the data dependent tasks are subjected to. This approach allows
accounting for preemptions induced by the cost of other preemptions. We
implemented a time measurement system on a LPC4080 microcontroller board of NXP
which includes the ARM Cortex M4 and several timers, to determine on the one
hand the actual cost of the scheduler and the cost of one preemption, and on
the other hand start, resume and completion times of every task of the task
sets. For the ARM Cortex M4 with a 120Mhz clock we obtained 142 cycles (2.3