On Mon, 24 Jan 2000, Davide Libenzi wrote:
> Monday, January 24, 2000 12:43 PM
> Pavel Machek <pavel@suse.cz> wrote :
> > Why not
> >
> > if ((c <= 0) && (nr_running >= smp_num_cpus)) /* To fix better */
> >
> > and define smp_num_cpus to 1 if case of UP system? [I think it already
> > _is_ defnied like this...]
>
> 100% agree.
That is a very bad plan. It would mean that the priority
of processes isn't recalculated during a period of low
cpu load.
That means that your running background process will have
a high priority when your needing-cpu-once-in-a-while
interactive task needs the CPU.
It also means that the priority of your interactive task
is lower than what it should be and that the priority of
the interactive task is higher than what it should be,
leading to worse interactive performance.
At least, that's what I think it does. I'd love to see
some test results from someone with enough time on their
hands -- you probably need about 3 days to fully explore
a scheduler and notice all of the strange things that
might happen...
(I've created a nice scheduler patch and it has taken me
some 3 days before I noticed one strange side effect of
the patch, even though I'd really done my best to try and
create as much different workloads as possible)
regards,
Rik
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This archive was generated by hypermail 2b29 : Mon Feb 07 2000 - 21:00:10 EST