Re: 2.5.47 scheduler problems?

Mike Galbraith
2002-11-18T07:34:17Z

----- Original Message -----
From: "Andrew Morton" <akpm@digeo.com>
To: "Tim Connors" <tconnors@astro.swin.edu.au>
Cc: <linux-kernel@vger.kernel.org>; "Mike Galbraith" <efault@gmx.de>
Sent: Monday, November 18, 2002 8:08 AM
Subject: Re: 2.5.47 scheduler problems?

> Tim Connors wrote:
> >
> > > 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?
> >
>
> No. He's saying that it used to be OK, but it has got worse.
>
> A much simpler test is to start a big compilation and then madly
> waggle an X window around. Goes OK for a few seconds, and then
> seizes up quite horridly. Presumably because the scheduler has
> suddenly decided that the X server has become a "batch" process
> and is scheduling it in a similar manner to the compilation.
>
> If you stop wiggling the window for 5-10 seconds it comes back.
> Presumably because the scheduler has decided that the X server is
> "interactive" again.
>
> When it happens, it's *very* bad. The mouse cursor doesn't move
> for 0.5-1.0 seconds and then takes great leaps. It is unusable.

I was watching it this morning, without wiggling, and it seems to update
window content (make output in one and vmstat in another) about every 5
seconds.. very odd looking.

-Mike