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Date: Sat, 02 Aug 2003 00:59:17 -0700
From: Terry Lambert <tlambert2@mindspring.com>
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To: John-Mark Gurney <gurney_j@efn.org>
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Subject: Re: Ultra ATA card doesn't seem to provide Ultra speeds.
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John-Mark Gurney wrote:
> Ruben de Groot wrote this message on Fri, Aug 01, 2003 at 10:15 +0200:
> > On Fri, Aug 01, 2003 at 04:33:08AM +0200, mh typed:
> > The following comparison is probably bogus, but can anybody explain the
> > huge difference?
> 
> It's called micro optimization.  Linux feels the need to special case
> /dev/zero to /dev/null, and instead of even reading/writing the data,
> It just ignores the user request, (or does something like set the pages
> in the user space to be zero'd.
> 
> Also, dual procs won't help your performance when you run a single
> process like this.

They will if you interleave the page zero'ing they do on both
CPU's... 8^p.

-- Terry