Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.2 9/5/84; site randvax.UUCP Path: utzoo!watmath!clyde!burl!ulysses!mhuxr!mhuxt!houxm!vax135!cornell!uw-beaver!tektronix!hplabs!sdcrdcf!randvax!edhall From: edhall@randvax.UUCP (Ed Hall) Newsgroups: net.arch Subject: Re: Cache revisited Message-ID: <2659@randvax.UUCP> Date: Wed, 21-Aug-85 00:31:16 EDT Article-I.D.: randvax.2659 Posted: Wed Aug 21 00:31:16 1985 Date-Received: Sun, 25-Aug-85 01:35:39 EDT References: <5374@fortune.UUCP> <901@loral.UUCP> <2583@sun.uucp> <5459@fortune.UUCP> Reply-To: edhall@rand-unix.UUCP (Ed Hall) Distribution: net Organization: Rand Corp., Santa Monica Lines: 18 Summary: Concerning the 68020's cache: I can think of a lot of places where a loop would fit in a 256-byte cache, especially in string-processing applications. Remember, in many applications a lot of time is spent simply copying memory, making searches, and so forth. This isn't just limited to strings: matrix operations usually include small inner loops where the bulk of computer time is spent. The same is true of bit-map graphics. And it is true for a lot of other CPU-hungry applications. So something close to a 50% hit rate wouldn't surprise me for a fairly large class of programs, though there is probably a larger class of programs that wouldn't do nearly that good. If Motorola were claiming it as an *average* I'd wonder who they thought they were fooling, but I don't believe they are doing so. -Ed Hall decvax!randvax!edhall