From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <fcdbb29608c689b6f83ca3a2b5539692@quanstro.net>
From: erik quanstrom <quanstro@quanstro.net>
Date: Thu, 17 Jul 2008 08:41:21 -0400
To: rvs@sun.com, 9fans@9fans.net
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Subject: Re: [9fans] 8 cores
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> > > I could imagine that databases use mmap() havily
> >
> > it's a little mystery for me why they would do that since it's slower (or ought to be),
>
> slower compared to what? I'd expect the biggest slowdown for
> read()/write() be not the price of a syscall, but what you
> pay for copying data in/out of the kernel. With mmap() there's
> no copying.

as you've pointed out, performance-wise it's not copying vs. nothing
it's copying vs page faults and trips through the vm code.
i would think playing vm games (as linus likes to say) would make
scheduling on mp harder

- erik