Re: [ck] Re: [PATCH][RSDL-mm 0/7] RSDL cpu scheduler for 2.6.21-rc3-mm2

[Con Kolivas <kernel@kolivas.org>]

On Tuesday 13 March 2007 20:21, Con Kolivas wrote:
> On Tuesday 13 March 2007 19:18, Ingo Molnar wrote:
> > * Mike Galbraith <efault@gmx.de> wrote:
> > > [...] The situation as we speak is that you can run cpu intensive
> > > tasks while watching eye-candy.  With RSDL, you can't, you feel the
> > > non-interactive load instantly. [...]
> >
> > i have to agree with Mike that this is a material regression that cannot
> > be talked around.
> >
> > Con, we want RSDL to /improve/ interactivity. Having new scheduler
> > interactivity logic that behaves /worse/ in the presence of CPU hogs,
> > which CPU hogs are even reniced to +5, than the current interactivity
> > code, is i think a non-starter. Could you try to fix this, please? Good
> > interactivity in the presence of CPU hogs (be them default nice level or
> > nice +5) is _the_ most important scheduler interactivity metric.
> > Anything else is really secondary.
>
> Well I guess you must have missed where I asked him if he would be happy if
> I changed +5 metrics to do whatever he wanted and he refused to answer me.
> That would easily fit within that scheme. Any percentage of nice value he
> chose. I suggest 50% of nice 0. Heck I can even increase it if he likes.
> All I asked for was an answer as to whether that would satisfy his
> criterion.

It seem Mike has chosen to go silent so I'll guess on his part. 

nice on my debian etch seems to choose nice +10 without arguments contrary to 
a previous discussion that said 4 was the default. However 4 is a good value 
to use as a base of sorts.

What I propose is as a proportion of nice 0:
nice 4 1/2
nice 8 1/4
nice 12 1/8
nice 16 1/16
nice 20 1/32 (of course nice 20 doesn't exist)

and we can do the opposite in the other direction
nice -4 2
nice -8 4
nice -12 8
nice -16 16
nice -20 32

Assuming no further discussion is forthcoming I'll implement that along with 
Al's suggestion for staggering the latencies better with nice differences 
since the two are changing the same thing.

-- 
-ck