Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!linus!philabs!cmcl2!rna!cubsvax!peters From: peters@cubsvax.UUCP (Peter S. Shenkin) Newsgroups: net.arch Subject: Re: Mips / MHz Message-ID: <475@cubsvax.UUCP> Date: Fri, 16-May-86 14:17:11 EDT Article-I.D.: cubsvax.475 Posted: Fri May 16 14:17:11 1986 Date-Received: Sun, 18-May-86 12:56:43 EDT References: <1363@unc.unc.UUCP> <467@cit-vax.Caltech.Edu> <384@astroatc.UUCP> <1774@gitpyr.UUCP> Reply-To: peters@cubsvax.UUCP (Peter S. Shenkin) Distribution: net Organization: Columbia Univ. Bio. CG Fac., NY Lines: 38 In article philm@astroatc.UUCP (Phil Mason) writes: >In article <1774@gitpyr.UUCP> kludge@gitpyr.UUCP (Scott Dorsey) writes: >>In article <384@astroatc.UUCP> philm@astroatc.UUCP (Phil Mason) writes: >>> >>>Power is defined to be the time rate at which work is done. That leaves us >>>in a little bit of a quandry. What is a unit of work for computer systems? >>>It must be related to how the CPU affects the information it processes. >> >> Your analogy with earlier machines is quite apt, except that it must be >>pointed out that, as mechanical devices do not all perform the same tasks, >>neither do computers perform the same tasks. >> Computing power CANNOT be measured in one scalar number. >>-- > >Yes, I agree. I didn't say it was going to be easy. > >Let's look at it this way. There are a number of generic information processing >functions that a computer performs : Floating point, Integer, Program >control flow and I/O operations. There are also subdivisions of these tasks >according to the size and type of the operands (i.e., scalar, vector, array - >8, 16, 32, 64+ bits etc.). Is performance on a particular program likely to be measurable as a linear combination of figures of merit for these tasks? For example, suppose you had a "MIPS"-like figure for floating point (FP), integer arithmetic (I), and looping (L). Suppose in some program running on a particular data set there were nfp FP instructions, ni, I instructions and nl times looping took place. Could we say, then, that performance on this program with this data set = nfp*FP + ni*I + nl*L ? What I really mean is, is there a list of "fundamental operations" which would constitute a such a linear space for performance, applicable to all or most machines? Or is the problem essentially non-linear? Peter S. Shenkin Columbia Univ. Biology Dept., NY, NY 10027 {philabs,rna}!cubsvax!peters cubsvax!peters@columbia.ARPA