Date: Fri, 02 Jun 1995 22:17:02 -0700 From: David Greenman <davidg@Root.COM> To: "Rodney W. Grimes" <rgrimes@gndrsh.aac.dev.com> Cc: henrich@crh.cl.msu.edu (Charles Henrich), freebsd-hackers@freebsd.org Subject: Re: A performance mystery Message-ID: <199506030517.WAA00138@corbin.Root.COM> In-Reply-To: Your message of "Fri, 02 Jun 95 22:10:47 PDT." <199506030510.WAA09409@gndrsh.aac.dev.com>
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>> > > 16 8192 3360694 2890287 > ^^^^^^^ > >How come *this* number and the number below are different by a factor >of 7??? It should have been the same. ``iozone 16 8192'' and the >above line from ``iozone auto'' do exactly the same things yet we >are seeing this *huge* descrepancy. Because there isn't enough 'free' memory at the time that he ran the test to cache the entire file. Since it's read sequentially and the cache policy for something like this is more or less LRU, it get pushed out of the cache before it is read back. -DG
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