On Apr 14,  4:40pm, Chuck Robey wrote:
} Subject: Re: swap-related problems
} On Wed, 14 Apr 1999, Anthony Kimball wrote:

} > Well, it's only needed if you want to be able to reliably execute ANSI 
} > C code according to spec.  I personally don't care.  I'd be surprised
} > if core didn't though.  I would suspect that it would be deemed worthy
} > of someone's p2 queue, at least.
} I can't understand this.  Make software that causes a major performance
} loss, and loses *bigtime* in memory allocation, just so the one guy to
} complain *at all* can not lose sleep over something that has causes no
} problems at all with any ANSI code in a properly sized system.

SunOS 4 doesn't do memory overcommit.  I've been running large processes
for years on SunOS 4 machines and haven't noticed any performance problems
due to lack of memory overcommit.  You just need to configure plenty of
swap.  I've found the old 3x RAM rule works fine, and it's really cheap
these days.  This could be shaved down a bit if SunOS didn't require
(swap > total VM) instead of (swap + RAM > total VM).

If you want to talk about slow, there are those crufty old implementations
that don't have COW fork().  If a large process forks, its entire memory
space needs to be duplicated, which is *really slow* if the process was
too big to fit in RAM to begin with.

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