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

Linus Torvalds
2001-05-02T19:35:04Z

In article <20010502211800.X805@mea-ext.zmailer.org>,
Matti Aarnio <matti.aarnio@zmailer.org> wrote:
>On Sun, Apr 29, 2001 at 02:16:43PM -0700, Jim Gettys wrote:
>...
>> "X is an exercise in avoiding system calls". I think I said this around
>> 1984-1985.
>> - Jim
>
>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