Re: Scheduler priorities

Robert Love (
29 Mar 2002 18:52:21 -0500

On Fri, 2002-03-29 at 16:42, Pavel Machek wrote:

> On each entry of kernel, promote SCHED_IDLE task to SCHED_NORMAL, and
> demote it at exit. This can be done with 0 overhad on hot paths.


> What's the problem with "promote at enter" approach? Using ptrace
> trick, it can be 0 overhead. [Was that your code that cleverly used
> ptrace?] What is problem with it?

There is no problem with the ptrace approach, it is good - I have
experimented with that solution myself. There is just a lot more to
SCHED_IDLE than "make the task only run when nothing else wants to" and
even the ptrace solution may involve a bit of work.

Robert Love

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at