[seL4] Re: MCS round-robin scheduling not behaving as expected

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"liam" == liam vervecken writes:

liam> Hello, I'm trying to understand MCS and how the scheduling works liam> but I'm running into some issues. My setup: RISCV on liam> BeagleVFire in sel4test liam> I have configured 2 threads: liam> seL4_SchedControl_ConfigureFlags(info->schedcontrol.start, liam> sched_context_thread2, 1000000, 1000000, 0, 0, 0); liam> seL4_SchedContext_Bind(sched_context_thread2, thread2_TCB); liam> seL4_SchedControl_ConfigureFlags(info->schedcontrol.start, liam> sched_context_thread3, 1000000, 1000000, 0, 0, 0); liam> seL4_SchedContext_Bind(sched_context_thread3, thread3_TCB); The only times that the seL4 kernel will preempt a running thread are: -- if a higher priority thread becomes runnable, or -- if the running thread runs out of budget. Your example sets budget==period so no thread will ever run out of budget and all threads will run until they wait on an event or call sched_yield(). To get the effect you want, set period to twice the budget, so each thread takes up half the available time. -- Dr Peter Chubb https://trustworthy.systems/ Trustworthy Systems Group CSE, UNSW Core hours: Mon 8am-3pm; Wed: 8am-5pm; Fri 8am-12pm.