Date: Thu, 21 Dec 2006 14:53:16 +0100 (CET) From: Oliver Fromme <olli@lurza.secnetix.de> To: freebsd-stable@FreeBSD.ORG, markir@paradise.net.nz Subject: Re: Cached file read performance with 6.2-PRERELEASE Message-ID: <200612211353.kBLDrG1M085224@lurza.secnetix.de> In-Reply-To: <458A5C04.9060109@paradise.net.nz>
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Mark Kirkwood wrote: > Exactly, that's why I did the comparison - I think you missed the part > where I mentioned the 2 systems were *identical* with respect to cpus, > memory, mobo - in fact even the power supplies are identical too! So I assume your benchmark measured the performance of the zero and null devices under FreeBSD and Linux. This is a quote from the "cstream" docs: "These special devices speed varies greatly among operating systems, redirecting from it isn't appropriate benchmarking and a waste of resources anyway." I suggest you try cstream (ports/misc/cstream) instead of dd. It supports built-in zero creation and data sink, so you don't have to use the zero and null devices at all, eliminating their overhead. It would be interesting how that will change your benchmark numbers. Best regards Oliver -- Oliver Fromme, secnetix GmbH & Co. KG, Marktplatz 29, 85567 Grafing Dienstleistungen mit Schwerpunkt FreeBSD: http://www.secnetix.de/bsd Any opinions expressed in this message may be personal to the author and may not necessarily reflect the opinions of secnetix in any way. "Life is short (You need Python)" -- Bruce Eckel, ANSI C++ Comitee member, author of "Thinking in C++" and "Thinking in Java"
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