Path: utzoo!utgpu!jarvis.csri.toronto.edu!clyde.concordia.ca!uunet!ibmpa!bass.tcspa.ibm.com!webb
From: webb@bass.tcspa.ibm.com (Bill Webb)
Newsgroups: comp.unix.aix
Subject: Re: Dhrystone 2.0 timings
Message-ID: <4378@ibmpa.UUCP>
Date: 6 Mar 90 23:36:38 GMT
References: <1990Feb27.230001.5373@jdyx.UUCP>
Sender: news@ibmpa.UUCP
Organization: IBM AWD Paloalto
Lines: 31

> RS 320 machine.  The results aren't quite what IBM stated (using V1.0), but
> that shouldn't be a big suprise.  :>  I got a value of 11,881.2
dhrystones/sec
> using a non-optimized version, and a value of 18,867.9 dhrystones/second
> using the optimizer.  Averages out to about 11 MIPS which isn't bad.  
>                                                   Shawn Hayes

I'm surprised that the numbers you are getting are so low. The number's 
I've been getting are somewhat higher (I don't think that I should post
them since I don't speak for IBM). The command I used to compile 

    cc -I/usr/include/sys -DLOOPS=500000 -DTIMES -DHZ=100 -Q -O dhry[12].c

note that you need to specify -DHZ=100 because a clock tick on an RS/6000
is 1/100 of a second. If you use the default (60 ticks/second) then you
will understate the results by about 40%. I think that specifying -Q
causes some functions to be inlined, which also improves the results.
In any case, when I compiled it without -Q and without -DHZ=100 I got 
numbers that were close (with 10%) of what you specified above.

With both -DHZ=100 and -Q I numbers that are about twice what you got.

I hope this helps explain some of the difference between the claimed
values and what you got. Note also that this is pre-release software and
that you may not have the same version of the compiler or system software
as I (or other people) do.

----------------------------------------------------------------
The above views are my own, not necessarily those of my employer.
Bill Webb (IBM AWD Palo Alto), (415) 855-4457.
UUCP: ...!uunet!ibmsupt!webb