Re: [ck] Re: [patch][rfc] quell interactive feeding frenzy

[Con Kolivas <kernel@kolivas.org>]

On Monday 17 April 2006 04:44, Andreas Mohr wrote:
> Hi,
>
> On Sun, Apr 16, 2006 at 09:22:59AM +1000, Con Kolivas wrote:
> > The current value, 6ms at 1000HZ, is chosen because it's the largest
> > value that can schedule a task in less than normal human perceptible
> > range when two competing heavily cpu bound tasks are the same priority.
> > At 250HZ it works out to 7.5ms and 10ms at 100HZ. Ironically in my
> > experimenting I found the cpu cache improvements become much less
> > significant above 7ms so I'm very happy with this compromise.
>
> Heh, this part is *EXACTLY* a fully sufficient explanation of what I was
> wondering about myself just these days ;)
> (I'm experimenting with different timeslice values on my P3/450 to verify
> what performance impact exactly it has)
> However with a measly 256kB cache it probably doesn't matter too much,
> I think.
>
> But I think it's still important to mention that your perception might be
> twisted by your P4 limitation (no testing with slower and really slow
> machines).

You underestimate me. Those cpu cache effects were performance effects 
measured down to a PII 233, but all were i386 architecture. As for 
"perception" this isn't my testing I'm talking about; these are 
neuropsychiatric tests that have nothing to do with pcs or what processor you 
use ;)

-- 
-ck