Date: Thu, 22 Apr 1999 16:29:48 -0500 (EST) From: Alfred Perlstein <bright@rush.net> To: mi@aldan.algebra.com Cc: questions@FreeBSD.ORG Subject: Re: writing slower with SoftUpdates Message-ID: <Pine.BSF.3.96.990422162747.2095C-100000@cygnus.rush.net> In-Reply-To: <199904212008.QAA57336@misha.cisco.com>
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On Wed, 21 Apr 1999, Mikhail Teterin wrote: > According to iozone, writing a 256M file to this empty 512M > fs works at > > 18247338 bytes/second without SoftUpdates > 16687585 bytes/second with SoftUpdates > > The results are repeatable with very little deviations. Reading speed > is about the same regardless of SoftUpdates and is around 13.9Mb/s. > > The disk is a 9Gb Cheetah LVD, attached to the LVD outlet of Adaptec's > 2940U2W. > > Another, identical Cheetah on the same SCSI cable, with another 512M > empty filesystem gives > > 18179755 b/s with SoftUpdates > 18315425 b/s without SoftUpdates > > Again, reading is not affected, but averages higher at around 18Mb/s. > > Are this results what one should expect? The only thing I can think of is that softupdates introduces longer code paths in the filesystem code for block accounting and meta data operations, for I/O intesive stuff it works great, but if your processor isn't that fast or you have benches that specifically mess with the softupdates code you'll probably get performance hits. -Alfred To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-questions" in the body of the message
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