Path: utzoo!mnetor!uunet!husc6!mailrus!umix!rutgers!mcnc!duke!gleicher
From: gleicher@duke.cs.duke.edu (Michael Gleicher)
Newsgroups: comp.sys.mac.programmer
Subject: Is my Mac II really slow?
Message-ID: <11541@duke.cs.duke.edu>
Date: 11 Apr 88 00:51:59 GMT
Organization: Duke University CS Dept.; Durham, NC
Lines: 60
Keywords: Mac II, floating point, benchmarks

Is my Mac II a dog? It is really 1/13th as fast as a MicroVax II (which is
a slow machine - much slower than say a Sun 3/60)?

Please look at what I've done and tell me what I've been doing wrong, and
how I can get some decent performance out of what I thought was a blazing
fast machine. I'd imagine something stupid and silly is going on like I'm
not using the floating point accelerator (68881) or that some processor time
is being eaten up on nonsense like updating the cursor.

The benchmark program I have is a simple ray tracing program. For the tests
of interest, all I/O is removed. It is a sheer test of double precision
floating point performance as it uses little memory.

I've tried LSC 2.15 and MPW. On MPW I had to use "extended" numbers otherwise
performance was unbearable. The machine is a stock Mac II with 5 Meg. 
In the chart MPW was used under Finder. LSC under multifinder gave very
similiar results (+-10%).

Here are the numbers:
	

	Ray Tracing Times

Machine		No I/O			File I/O
		user	elapsed		user		elapsed

Vax8600		6.63	7		13.017		15
MV20000		7.95	4 ????		21.183		14 ??
uVax II		33.75	35		104.3		107
Mac II(a)		474.1

(a) compiler = MPW, extended used instead of double as it is faster

all trails were run on lightly loaded machines
8600 = duke
MV/20000 = dukee
uVaxII = elmer

Something is definately wrong. The code required NO changes to move
from the Mac to the Vax (when developed with LSC). I will give the code
to anyone who wants to look at it. It's only about 300 lines long.

If someone could tell me how to use the 68881 and put some assembly into
my Mac program, or tell MPW to write native code 68881 and use 68020
instructions (I'm sure there must be a compiler option to do this, but
"Help C" only mentions 68010 Could it be our MPW is old?). An assembly
function that would take the place of the C function:
	extended dot(x1,y1,z1,x2,y2,z2)
	{ return(x1*x2+y1*y2+z1*z2);}
would be enough of an example so I could figure the rest out.

Thanks for help. I'm sure I'm just doing something stupid.

Thanks,
	Mike

Michael Lee Gleicher			(-: If it looks like I'm wandering
	Duke University			(-:    around like I'm lost . . .
E-Mail: gleicher@cs.duke.edu)(or uucp	(-:
Or P.O.B. 5899 D.S., Durham, NC 27706	(-:   It's because I am!