Re: [2.4.17/18pre] VM and swap - it's really unusable

Mark Hahn
2002-01-21T19:25:24Z

> > > To me the benefit is clear enough: ASAP scheduling of IO threads, a
> > > simple heuristic that improves both throughput and latency.
> >
> > I think of "benefit", perhaps naiively, in terms of something that can
> > be measured or demonstrated rather than just announced.
>
> But you see why asap scheduling improves latency/throughput *in theory*,
> don't you?

NO, IT DOES NOT. why can't you preempt-ophiles get that through your heads?

eager scheduling is NOT optimal in general.

for instance, suppose my disk can only read a sector at a time.
scheduling my sequentially-reading process to wake eagerly
is most definitly PESSIMAL. laziness is a cardinal virtue!
this doesn't preclude heuristics to sometimes short-cut the laziness.