Path: utzoo!mnetor!uunet!lll-winken!lll-tis!elxsi!len
From: len@elxsi.UUCP (Len Mills)
Newsgroups: comp.arch
Subject: Re: What's a Vax 11/780 MIP really?
Message-ID: <748@elxsi.UUCP>
Date: 16 Mar 88 18:53:31 GMT
References: <413@mn-at1.UUCP>
Reply-To: len@elxsi.UUCP (Len Mills)
Organization: ELXSI Super Computers, San Jose
Lines: 40

In article <413@mn-at1.UUCP> alan@mn-at1.UUCP (Alan Klietz) writes:
>We all know what a VAX "MIPS" is, right?  But have you ever
>bothered to actually measure it?  DEC did.  A recent column in one of
>the Unix trade mags reveals that the Vax 780 = 1 MIPS rule-of-thumb
>may be grossly overstated.
>
>Therefore one VAX 780 "MIPS" is approximately 0.44 "honest-to-god"
>VAX MIPS?  (HTGV MIPS?)   Or a 126% overestimate?
>
  I offer a tiny bit of (probably well-known) historical perspective.

  Many moons ago, in the dim ages of the past, ITEL's System Development
  Division performed some measurements on an IBM 370/158 clone (AS-5)
  using an event counter driven by "EndOP" (microcode end-of-instruction)
  which yielded 1.08 MIPS over a 36-hour period.  Hourly rates varied
  between 1.01 and 1.20.    Common industry usage rated the 158 at
  one MIP.  It also rated the 158 at 2X a 780.

  From this usage comes the old rule-of-thumb that an IBM MIP is 2X
  a VAX MIP.  This rule is still in common use among business oriented
  computer publications.

  Since this group is primarily interested in scientific usage rather
  than business usage, perhaps the continued use of VUPS is justified.
  I don't want all the flamage that would arise from proposing the use
  of IBM MIPS.

>--
>Alan Klietz
>Minnesota Supercomputer Center (*)
>1200 Washington Avenue South
>Minneapolis, MN  55415    UUCP:  alan@mn-at1.k.mn.org
>Ph: +1 612 626 1836       ARPA:  alan@uc.msc.umn.edu  (was umn-rei-uc.arpa)
>
>(*) An affiliate of the University of Minnesota


-- 

Len Mills ...
{uunet,ucbvax!sun,lll-lcc!lll-tis,altos86,bridge2}!elxsi!len