Date: Sat, 02 Aug 2003 00:59:17 -0700 From: Terry Lambert <tlambert2@mindspring.com> To: John-Mark Gurney <gurney_j@efn.org> Cc: mh <mh@nerim.net> Subject: Re: Ultra ATA card doesn't seem to provide Ultra speeds. Message-ID: <3F2B6F55.DDF626C3@mindspring.com> References: <200307311219.h6VCJLVG053962@spider.deepcore.dk> <20030801082658.GQ10708@funkthat.com>
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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
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