On 2018-09-26 17:07:02 [+0200], Ralf Ramsauer wrote: > Hi, Hi, > But if I synchronously send a SIGALRM via kill, it will immediately > arrive. Even a sched_yield() in the busy loop won't help. In order to > get the signal, I have to leave running/runable with usleep(). a sched_yield() will put you at the end of the runqueue. If this is the only task in that queue then the task will go back on the CPU. > Thanks > Ralf Sebastian