High Resolution Timer DOS

From: matthieu castet
Date: Sat Apr 28 2007 - 17:54:24 EST


some programs need to do some short of busyloop. It was often implemented as :

while (1) {
if (can_do_stuff) {
//sleep a very short of time

usleep(1) or equivalent where used instead of sched_yield, because of some priority issue. IIRC doing sched_yield, make the process appears like an interactive process, so it has better priority and get call more often.

But now if high res timer are enabled, these programs while cause something like a DOS : the context switch per second will be bigger than 500 000 and the cpu usage will be very high.

I don't know if such problem are already know, but I believe a warning about such issues should be in the Kconfig description.

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