Re: [RFC][PATCH] Make MAX_RT_PRIO and MAX_USER_RT_PRIO configurable

From: Esben Nielsen
Date: Wed Jul 27 2005 - 09:54:23 EST


On Wed, 27 Jul 2005, Ingo Molnar wrote:

>
> * Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> > Perfectly understood. I've had two customers ask me to increase the
> > priorities for them, but those where custom kernels, and a config
> > option wasn't necessary. But since I've had customers asking, I
> > thought that this might be something that others want. But I deal
> > with a niche market, and what my customers want might not be what
> > everyone wants. (hence the RFC in the subject).
> >
> > So if there are others out there that would prefer to change their
> > priority ranges, speak now otherwise this patch will go by the waste
> > side.
>
> i'm not excluding that this will become necessary in the future. We
> should also add the safety check to sched.h - all i'm suggesting is to
> not make it a .config option just now, because that tends to be fiddled
> with.
>
Isn't there a way to mark it "warning! warning! dangerous!" ?

Anyway: I think 100 RT priorities is way overkill - and slowing things
down by making the scheduler checking more empty slots in the runqueue.
Default ought to be 10. In practise it will be very hard to have
a task at the lower RT priority behaving real-time with 99 higher
priority tasks around. I find it hard to believe that somebody has an RT
app needing more than 10 priorities and can't do with RR or FIFO
scheduling within a fewer number of prorities.

Esben

> Ingo
> -
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/