Date: Mon, 20 Mar 1995 19:13:00 +0100 From: Wolfram Schneider <wosch@cs.tu-berlin.de> To: "Christoph P. Kukulies" <kuku@gilberto.physik.rwth-aachen.de> Cc: freebsd-current@freefall.cdrom.com Subject: iozone read vs. write Message-ID: <199503201813.TAA16838@caramba.cs.tu-berlin.de> In-Reply-To: <199503201602.RAA02319@gilberto.physik.rwth-aachen.de> References: <199503201602.RAA02319@gilberto.physik.rwth-aachen.de>
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Christoph P. Kukulies writes: > iozone 13 ... > > Writing the 13 Megabyte file, 'iozone.tmp'...15.085938 seconds > Reading the file...4.000000 seconds > > IOZONE performance measurements: > 903589 bytes/second for writing the file > 3407872 bytes/second for reading the file > > Does anone have an explanation why the number diverge to such an extent? > (System is a 32 MB 486DX2/66 EIDE 2 Quantum 540 system) Ja. $ more REAMDE In order for this to be a fair test, the length of the test file must be AT LEAST 2X the amount of disk cache memory for your system. If not, you are really testing the speed at which your CPU can read blocks out of the cache (not a fair test) Wolfram
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