Re: low priority soft RT?

Rik van Riel (riel@humbolt.nl.linux.org)
Tue, 27 Jul 1999 16:04:12 +0200 (CEST)


On Tue, 27 Jul 1999 yodaiken@chelm.cs.nmt.edu wrote:

> I still don't understand the purpose of SCHED_IDLE. It seems as if the
> only purpose is to slow down general execution by a couple of percent

> Someone, maybe it was Linus, pointed out that the current range of
> "nice" levels is totally arbitrary and simply increasing the range
> would do good.

Unfortunately, we showed him he was wrong and the deadlock
could still happen with normal timeslicing processes and
RT tasks...

SCHED_IDLE adds nothing new and has just as little chance
of hanging the computer as normal system things. Because of
this, my patch adds a sysctl variable that the sysadmin has
to switch before normal users are allowed the use of SCHED_IDLE.

This allows the more careful sysadmins to use SCHED_IDLE for,
for instance, rc5des while not impacting normal system behaviour
or stability.

Rik -- Open Source: you deserve to be in control of your data.
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