Re: 2.6.21-rc3-mm1 RSDL results

Con Kolivas
2007-03-09T20:16:04Z

On Saturday 10 March 2007 05:27, Matt Mackall wrote:
> On Fri, Mar 09, 2007 at 07:39:05PM +1100, Con Kolivas wrote:
> > On Friday 09 March 2007 19:20, Matt Mackall wrote:
> > > And I've just rebooted with NO_HZ and things are greatly improved. At
> > > idle, Beryl effects are silky smooth (possibly better than stock) and
> > > shows less load. Under 'make', Beryl is still responsive as is Galeon.
> > > No sign of lagging mouse or typing.
> > >
> > > Under make -j 5, things are intermittent. Galeon scrolling is
> > > sometimes still responsive, but Beryl, terminals and mouse still drag
> > > quite a bit.
> >
> > I just replied before you sent this one out I think our messages passed
> > each other across the ocean somewhere. I don't quite get what combination
> > of factors you're saying here caused great improvement. Was it enabling
> > NO_HZ on mainline cpu scheduler or disabling NO_HZ or on RSDL?
>
> Turning on NO_HZ on RSDL greatly improved it. I have not tried NO_HZ
> on mainline. The first test was with NO_HZ=n, the second was with
> NO_HZ=y.

How odd. I would have thought that if an interaction was to occur it would
have been without the new feature. Clearly what you describe without NO_HZ is
not the expected behaviour with RSDL. I wonder what went wrong. Are you on
100HZ on that laptop? While I expect 100HZ should be ok, it might just not
be... My laptop is about the same performance and works fine with 100HZ under
load of all sorts BUT I don't have Beryl (which I would have thought swayed
things in the opposite direction also).

> As an aside, we should not name config options NO_* or DISABLE_*
> because of the potential for double negation.

Case in point, I couldn't figure out what you were saying :)

--
-ck