Path: utzoo!news-server.csri.toronto.edu!bonnie.concordia.ca!ccu.umanitoba.ca!herald.usask.ca!alberta!aunro!aupair.cs.athabascau.ca!atha!decwrl!elroy.jpl.nasa.gov!usc!rpi!uupsi!sunic!kth.se!news From: ulfis@cyklop.nada.kth.se (Anders Ulfheden) Newsgroups: comp.sys.mac.programmer Subject: Re: Settings of cache-memory vs system performance Message-ID: Date: 13 Mar 91 20:42:49 GMT References: <4745.27DDB399@stjhmc.fidonet.org> Sender: news@kth.se (News Administrator) Organization: Royal Institute of Technology, Stockholm, Sweden Lines: 22 In-reply-to: Lawson.English@p88.f15.n300.z1.fidonet.org's message of 11 Mar 91 18:09:23 GMT In article <4745.27DDB399@stjhmc.fidonet.org> Lawson.English@p88.f15.n300.z1.fidonet.org (Lawson English) writes: > Anders Ulfheden writes in a message to All > > AU> When playing around with Speedometer for measuring system performance > AU> I have noticed that turning the cache memory ON, reduces the > AU> speed in some cases with a factor 2! > > Just a guess, assuming that ON and OFF aren't mixed up: perhaps there is an > overhead to "load the cache" that is noticable when a long *sequence* of instructions > is executing instead of a (short) loop. Which CPU are you running? This test has been done on SI and LC, both with and without coprocessor. The same behavior. So, answer to your question: 68020 and 030. Ulfis -- +------------------------------------------------------------------------------ | Anders Ulfheden | USENET: ulfis@nada.kth.se | Royal Institute of Technology | Stockholm, Sweden