Re: [RFC][PATCH][2.6.6] Replacing CPU scheduler active and expired with a single array

[Con Kolivas <kernel@kolivas.org>]

On Fri, 28 May 2004 19:24, Peter Williams wrote:
> Ingo Molnar wrote:
> > just try it - run a task that runs 95% of the time and sleeps 5% of the
> > time, and run a (same prio) task that runs 100% of the time. With the
> > current scheduler the slightly-sleeping task gets 45% of the CPU, the
> > looping one gets 55% of the CPU. With your patch the slightly-sleeping
> > process can easily monopolize 90% of the CPU!

> This does, of course, not take into account the interactive bonus.  If
> the task doing the shorter CPU bursts manages to earn a larger
> interactivity bonus than the other then it will get more CPU but isn't
> that the intention of the interactivity bonus?

No. Ideally the interactivity bonus should decide what goes first every time 
to decrease the latency of interactive tasks, but the cpu percentage should 
remain close to the same for equal "nice" tasks. Interactive tasks need low 
scheduling latency and short bursts of high cpu usage; not more cpu usage 
overall. When the cpu percentage differs significantly from this the logic 
has failed.

Con