Re: 2.5.47 scheduler problems?

From: Tim Connors (tconnors@astro.swin.edu.au)
Date: Mon Nov 18 2002 - 02:53:01 EST


On Mon, 18 Nov 2002, Mike Galbraith wrote:

> > > If I do the same in 2.5.47, I have no control of my box. Setting
> all tasks
> > > to SCHED_FIFO or SCHED_RR prior to starting make -j10 bzImage, I can
> regain
> > > control, but interactivity under load is basically not present.
> >
> > Funny that.
> >
> > > I used to be able to wave a window poorly at make -j25 (swapping
> heftily),
> > > fairly smoothly at make -j20, and smoothly at make -j15 or below.
> This
> > > with no SCHED_RR/SCHED_FIFO. (I haven't done much testing like this
> in
> > > quite a while though)
> >
> > Perhaps you should consider buying an extra 29 CPU's for you desktop?
>
> I have neither the need for 30 CPUs, nor the cash to pay for such a
> beast :)
>
> I gather you think my test is silly?

Well, yes, 30 processes at a time on a single CPU does seem a bit silly -
given that (under the old system), you would not expect X to get more than
3% of the CPU time.
Also sceduling normal processes (ie, not real-time processes) as RR/FIFO
seemed also pretty bad.

However....

But I have to now admit that I haven't yet played with 2.5.47 seriously,
and wansn't aware of the problems which Andrew just posted.

mea culpa.

-- 
TimC -- http://astronomy.swin.edu.au/staff/tconnors/

If you ever fear that machines will surpass humans in intelligence, just ask Microsoft to write the OS. -- POTU in RHOD

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