Re: X15 alpha release: as fast as TUX but in user space (fwd)

[Fabio Riccardi]

What costs a lot is moving data around, since modern CPUs spend most of their
time in memory/bus wait cycles...

 - Fabio

Linus Torvalds wrote:

> >I think that applies to all really high-performance servers.
>
> Note that it is definitely not always true.
>
> Linux system calls are reasonably light-weight.  And sometimes trying to
> avoid them ends up beaing _more_ work - because you might have to worry
> about synchronization and cache coherency in user mode.
>
> So the rule should be "avoid _unnecessary_ system calls".
>
>                 Linus
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