On 22 Apr 2001, Francis Litterio wrote:
> I'm reading Rubini's "Linux Device Drivers" and it isn't clear to me
> whether the scheduler runs every time the timer interrupt increments
> jiffies or less frequently.
>
> Does the scheduler run every time jiffies is incremented?
No. Every timer interrupt a bunch of functions in
kernel/timer.c is run, amongst them the following lines
of code (from update_process_times):
if (--p->counter <= 0) {
p->counter = 0;
p->need_resched = 1;
}
As you can see, we will only reschedule when the time slice
of the currently running process is over.
regards,
Rik
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