Messages in this thread | | | Date | Tue, 11 May 1999 16:55:42 +0200 (CEST) | From | Ingo Molnar <> | Subject | Re: [patch] new scheduler |
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On Tue, 11 May 1999, Andrea Arcangeli wrote:
> >not necesserily, it might as well just be replaced by a RT process ... > > If the `prev' process is RT and the `prev' task is been preemted it means > that all other CPUs are just running RT task too. So it wouldn't be > worthwhile again.
Just think about it for a second: if you preempt a RT task with another RT task (yes this is possible, and yes, this is a RL example), then we immediately want to 'push' that RT task to another CPU. Also there are other, non-RT cases where 'pushing' a process to another processor makes sense. (just think about different static process priorities for a second)
> >> I repeat that as global design I prefer to have such call in schedule_tail > >> even if according to me it's only a performance _hit_. ^^^^^^^^^^^^^^^^^^^^ > > > >it is not a performance hit at all because most processes reschedule > >'voluntarily', ie. they get removed from the runqueue. > > I just said you that in such case the call is not needed. [...]
then why do you say it's a performance hit? It's something we need for correctness, it doesnt affect the common case, where is your problem?
-- mingo
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