linux-kernel-digest V1 #113

[Horst von Brand]

Steve Underwood <steveu en coppice.org> said:
> Robert Dinse wrote:

[...]

> >      Since the scheduler is adaptive, the new code, other than the
> > test, is only going to executed under the heavy load conditions.
> > Surely the test isn't 1kbyte or anywhere close to it?

> A partially good point, but flawed.

> In the reasonable load case most of the new code won't necessarily get
> into the cache, so it should have little impact.

But one instruction more to fetch from RAM is a _huge_ cost, relatively
speaking. There is also the cost of making sure this whole machinery works
right each time it is tweaked.

> Now consider the high load case. A high load means the machine is being
> crippled by multiple number crunching activities creating a compute
> requirement beyond the system's reasonable means. [...]

And this being so, no amount of tweaking will fix it. Leave it alone, that
is simpler and has the same result: You need a a bigger machine.
-- 
Horst von Brand                             vonbrand en sleipnir.valparaiso.cl
Casilla 9G, Viña del Mar, Chile                               +56 32 672616


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