A different metric for scheduler optimisation

[Horst von Brand]

Davide Libenzi <dlibenzi en maticad.it> said:
> On Sat, 29 Jan 2000, Horst von Brand wrote:
> > In case your application switches rapidly, it is thrashing the cache, which
> > is crucial for performance with current CPUs. You simply don't want to do
> > that, ever. You get best performance by _never_ switching unless forced to
> > do so, but that isn't realistic.

> If You switch fast You have more cache reloads of probably less cache lines (
> or pages ).

Yep. You don't even get to build up your working set that way. Just cache
misses, no real work done.

> Since a task that run a short time has a lower probability to "touch" RAM
> locations.

It also hasn't got time enough to use the RAM locations it got into cache
for more than a few times.

This obviously depends on the exact behaviour of processes and cache use.
-- 
Horst von Brand                             vonbrand en sleipnir.valparaiso.cl
Casilla 9G, Viña del Mar, Chile                               +56 32 672616

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