[trying not to flame!]
no CPU in the world has memory writes for free! i'll rephrase if its
hard to understand - the _performance_ effect is not "twice the time" but
relative to the cpu/bus speed, but the _absolute_ time spent is (+/-
depending on bus design).
also, it doesn't matter if it's not noticeable on a modern P2, because
we're not talking about P2's here and just because the 10/100 load on a P2
is ok now doesn't mean it will be tomorrow. grrrrr whatever happened to
complexity theory in school...
> > Fact: our HW, while sending TCP on a 100 mbit/s ethernet, spends 70% of
> > the time in csum_partial_copy. I'd be surprised if the performance of the
> > transfers wouldn't go up quite alot if that call was eliminated.
>
> what hw is that?
an embedded network cpu, 100 mips. the cycles spent on copying are much
better spent doing something useful.
[rant on]
the sort of thinking that goes "it's not noticeable on a $500 CPU right
now so we don't have to care" is what keeps M$ programs slow and intel
rich.
/bjorn
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