Re: Off-topic: what is bogoMIPS?

[Brian Servis <servis@purdue.edu>]

*- On 12 May, Hans van den Boogert wrote about "Off-topic: what is bogoMIPS?"
> I understand what MIPS is (Million Instructions per Second), but what does
> the bogo stand for? My 486-33 measures 4 bogoMIPS during Linux boot-up, so
> how is this calculated? -Hans
> 
> 

see /usr/doc/HOWTO/mini/BogoMips.gz

       `MIPS is short for Millions of Instructions Per Second.  It
       is a measure for the computation speed of a program.  Like
       most such measures, it is more often abused than used prop<AD>
       erly (it is very difficult to justly compare MIPS for dif<AD>
       ferent kinds of computers).

       BogoMips are Linus's invention. The kernel (or was it a
       device driver?) needs a timing loop (the time is too short
       and/or needs to be too exact for a non-busy-loop method of
       waiting), which must be calibrated to the processor speed of
       the machine. Hence, the kernel measures at boot time how
       fast a certain kind of busy loop runs on a computer. "Bogo"
       comes from "bogus", i.e, something which is a fake. Hence,
       the BogoMips value gives some indication of the processor
       speed, but it is way too unscientific to be called anything
       but BogoMips.

       The reasons (there are two) it is printed during bootup is
       that a) it is slightly useful for debugging and for checking
       that the computers caches and turbo button work, and b)
       Linus loves to chuckle when he sees confused people on the
       news.'

-- 
Brian 
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Mechanical Engineering                              servis@purdue.edu
Purdue University                   http://www.ecn.purdue.edu/~servis
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