Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!uunet!husc6!bbn!kgregory From: kgregory@bbn.COM (Keith D. Gregory) Newsgroups: comp.lang.c Subject: Re: Dhrystones Message-ID: <5096@ccv.bbn.COM> Date: Thu, 3-Dec-87 10:28:21 EST Article-I.D.: ccv.5096 Posted: Thu Dec 3 10:28:21 1987 Date-Received: Mon, 7-Dec-87 02:19:34 EST References: <3368@rosevax.Rosemount.COM> Reply-To: kgregory@ccv.bbn.com.BBN.COM (Keith D. Gregory) Organization: Bolt Beranek and Newman Inc., Cambdridge MA Lines: 29 Keywords: C, performance, useful Summary: Here we go . . . In article <3368@rosevax.Rosemount.COM> richw@rosevax.Rosemount.COM (Rich Wagenknecht) writes: >Could somemone tell me what a 'Dhrystone' (<-sp.?) is? >Why is it used so often to evaluate compiler performance? >Is it a good overall indicator of compiler peformance? Well, we all know that benchmarks are invalid :-) The dhrystone benchmark produces a number which lets you know how efficiently your compiler/computer can perform integer operations (as opposed to Whetstone, which is FP, and yes, I know that the compiler doesn't perform anything except a compilation :-) As I see things, there are two uses for Dhrystone: 1 - Compare different compilers for a given machine. I find this to be very useful - although there are certainly many factors contributing to the efficiency of compiled code, I've found that Dhrystone figures give a fairly accurate comparison of two compilers (as I see it, if a compiler writer makes efficient integer procesing code, the system calls will probably be efficient too). 2 - Having a number to hang your hat on. Let's face it, when I say that my 20MHz 386, running Xenix-386 can turn 4800 dhrystones/second (and it can :-), that's bound to impress the hexk out of someone using a Mac which turns 1000. . .never mind that there are vast differences between the two machines/compilers ;-) -kdg