Path: utzoo!attcan!uunet!decwrl!wuarchive!zaphod.mps.ohio-state.edu!samsung!noose.ecn.purdue.edu!mentor.cc.purdue.edu!mace.cc.purdue.edu!abe From: abe@mace.cc.purdue.edu (Vic Abell) Newsgroups: comp.arch Subject: Re: Workstation Disk I/O Summary: IOStone really is BufferCacheStone. Message-ID: <5725@mace.cc.purdue.edu> Date: 9 Oct 90 14:46:35 GMT References: <14900016@hpdmd48.boi.hp.com> <2387@van-bc.wimsey.bc.ca> <143502@sun.Eng.Sun.COM> Organization: Purdue University Lines: 19 In article <143502@sun.Eng.Sun.COM>, lm@slovax.Sun.COM (Larry McVoy) writes: > In article <2387@van-bc.wimsey.bc.ca> jtc@van-bc.wimsey.bc.ca (J.T. Conklin) writes: > >In article <14900016@hpdmd48.boi.hp.com> sritacco@hpdmd48.boi.hp.com (Steve Ritacco) writes: > > IOstone is misnamed and misleading. It ought to be called "cachestone" or > "buffer cachestone". It does *not* measure I/O performance. It measures > cache performance. Agreed. I've had a chance to run IOStone on a number of different systems. I found one machine with an extremely aggressive buffer cache mechanisim and SCSI bus I/O (not a Sun :-) whose IOStone rating exceeded that of a Cray YMP. It is very difficult to disable the effect of a good buffer cache when you really want to measure I/O device or channel speed. So far I've not seen any test that does a good job of that, nor have I been able to construct one myself. Vic Abell