Brian Hurt <bhurt@talkware.net> said:
> This discussion is rapidly degenerating into a "does too!" "does not!"
> match. So let me turn the question around. Assume, for a moment, that a
> patch for Linux existed which did two things:
> 1) Ran signifigantly faster for large run queues- for example it switched
> from the current O(n) algorithm to an O(log n) algorithm.
> 2) Ran slower than the current scheduling algorithm for short run
> queues.
> And the patch had no other effects on the kernel at large and was
> otherwise well written, etc.
> Am I right in assuming that wether the patch would be accepted would
> depend upon how much slower it made the common case? Obviously, if it
> made the common case no slower, no one would mind putting it in the
> kernel. On the other hand, if it made the common case a million times
> slower, there is no way it'd ever get into the kernel, and rightfully so.
> Where (roughly) inbetween is the breakpoint?
When it doesn't make runqueues of length 1 (typical, _optimal_ case) slower
at all. OTOH, this happens once a timeslice, let's say 5 to 100 times a
second, so it is simply not performance critical
-- Horst von Brand vonbrand@sleipnir.valparaiso.cl Casilla 9G, Viņa del Mar, Chile +56 32 672616- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
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