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In article <201@dg.dg.com> uunet!dg!rec (Robert Cousins) writes:
>I apparently did not make my point clear.   Let me try it again:
>
>	There has been a somewhat widespread use do the term 
>	"Dhrystone MIPS" in the industry. This is commonly
>	linked to some actual measure of performance.  There
>	has been fast and loose use of this term interchangeably
>	with the other relatively useless measure of performance
>	MIPS.  Not only are these two measures not the same but
>	they are only of limited applicability.  The example I
>	gave earlier where Dhrystone MIPS > Raw MIPS disproves
>	the similarity.

I still think you're misunderstanding.  "Dhrystone MIPS" have nothing
whatsoever to do with "Raw MIPS".  I define "Raw MIPS" to be the number of
millions of native instructions per second that a system executes for a given
application.  This value might be interesting in some quarters, but it's
generally useless in comparing different architectures.

If we assume that by "MIPS" you mean "VUPS", or some value relative to a
VAX/780 (running some specified compilers and OS), then the term "Dhrystone
MIPS" (or "Dhrystone VUPS") was coined as a caveat to explain how a particular
system's MIPS "rating" was computed.  You can choose a spectrum of benchmarks
and compute some kind of reasonable mean performance value, or you can pick
one benchmark which shows the highest value, albeit an unrepresentative one.
Dhrystone is one such benchmark.  This is like an auto manufacturer claiming
a miles-per-gallon rating based upon 45 MPH steady highway driving.  Fine, but
don't try to compare this value with everyone else's values which are computed
differently.  "Dhrystone MIPS" is to "MIPS" (=="VUPS") as "Highway Mileage"
is to "Mileage".  And none of these things has anything to do with "Raw MIPS".

-- 

John Hawkes
{ames,decwrl}!mips!hawkes  OR  hawkes@mips.com