Messages in this thread | | | Subject | Re: report a bug about sched_rt | From | Peter Zijlstra <> | Date | Fri, 24 Jul 2009 15:14:50 +0200 |
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Don't top post -- again!
On Fri, 2009-07-24 at 21:04 +0800, sen wang wrote: > Linux is used in many fieldes. SCHED_OTHER tasks is important to > embedded system.
Irrelevant.
> if there is a running state task(a realtime task), how can we > shcedule the idle task up?
Because it ran out of bandwidth.
> It is ridiculous! > > since the throttle has a bug, why not fix it?
It doesn't have a bug, therefore I won't fix it.
The throttle limits the RT tasks to a bandwidth w of u/p. Since real-time scheduling is about determinism a maximum bandwidth larger than the minimum bandwidth specified by w is useless since it cannot be relied upon.
Therefore we don't run RT tasks beyond their bandwidth limit.
Go read up on scheduling theory.
Now you might want a bandwidth of 100% for your RT application (not something I can recommend for the overall health of your machine) in which case you're free to change this setting:
echo -1 > /proc/sys/kernel/sched_rt_runtime_us
Should do that for you. Also read:
Documentation/scheduler/sched-rt-group.txt
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