Re: [BENCHMARK] scheduler tunables with contest - prio_bonus_ratio

[Andrew Morton <akpm@digeo.com>]

Robert Love wrote:
> 
> ...
> Not too sure what to make of it.  It shows the interactivity estimator
> does indeed help... but only if what you consider "important" is what is
> considered "interactive" by the estimator.  Andrew will say that is too
> often not the case.
> 

That is too often not the case.

I can get the desktop machine working about as comfortably
as 2.4.19 with:

# echo 10 > max_timeslice 
# echo 0 > prio_bonus_ratio 

ie: disabling all the fancy new scheduler features :(

Dropping max_timeslice fixes the enormous stalls which happen
when an interactive process gets incorrectly identified as a
cpu hog.  (OK, that's expected)

But when switching virtual desktops some windows still take a
large fraction of a second to redraw themselves.  Disabling the
interactivity estimator fixes that up too.  (Not OK.  That's bad)

hm.  It's actually quite nice.  I'd be prepared to throw away
a few cycles for this.

I don't expect the interactivity/cpuhog estimator will ever work
properly on the desktop, frankly.  There will always be failure
cases when a sudden swing in load causes it to make the wrong
decision.

So it appears that to stem my stream of complaints we need to
merge scheduler_tunables.patch and edit my /etc/rc.local.