| Impressions of IDL on PowerMac vs. Sparc [message #3471] |
Tue, 31 January 1995 10:33  |
Jeff Bloch
Messages: 4
Registered: January 1995
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Junior Member |
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We have just started playing with IDL on a Power Mac (Quadra 650 with Power
Mac upgrade card, (6100/66 equivalent) with 40MB of memory) and comparing it
to IDL running on a Sparc LX. We have found some very interesting speed
differences. Simple large array operations are a factor of two FASTER on the
Power Mac than on the Sparc, yet transcendental function array operations
(sin, asin, tan, etc) appear to be a factor of two SLOWER on the Power Mac.
Array operations using sqrt() also appear to be faster on the Power Mac.
Operations using the convol() function are also much faster on the Power Mac.
On the other hand, running the standard IDL demo on each shows the Power Mac
running the demo ~40% slower. The Sparc LX did not page or swap during the
tests.
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Jeffrey Bloch Office: (505) 665-2568
Astrophysics and Radiation Measurements Group ALEXIS Soc: (505) 665-5975
Los Alamos National Laboratory FAX: (505) 665-4414
Group NIS-2, Mail Stop D436 e-mail: jbloch@lanl.gov
Los Alamos, NM 87545
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| Re: Impressions of IDL on PowerMac vs. Sparc [message #3535 is a reply to message #3471] |
Thu, 02 February 1995 12:52  |
walsteyn
Messages: 3
Registered: December 1993
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Junior Member |
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In <Pine.CVX.3.90.950131111953.24952A-100000@sstcx1.lanl.gov> Jeff Bloch <jbloch@sstcx1.lanl.gov> writes:
> We have just started playing with IDL on a Power Mac (Quadra 650 with Power
> Mac upgrade card, (6100/66 equivalent) with 40MB of memory) and comparing it
> to IDL running on a Sparc LX. We have found some very interesting speed
> differences. Simple large array operations are a factor of two FASTER on the
> Power Mac than on the Sparc, yet transcendental function array operations
> (sin, asin, tan, etc) appear to be a factor of two SLOWER on the Power Mac.
You might get a higher speed on the PowerMac if you would install
a new floating point math library (made by Apple). It's called MathLib.
Ask or read about it in a comp.sys.mac.* newsgroup. (I don't know the
details as I don't have a PowerMac. The only thing I do know is that
the MathLib in ROM is ``slow'' when it comes to transcendental functions...
The software patch, i.e., the MathLib extension, solves the speed problem.)
Good luck,
Fred. (walsteyn@fys.ruu.nl)
> Array operations using sqrt() also appear to be faster on the Power Mac.
> Operations using the convol() function are also much faster on the Power Mac.
> On the other hand, running the standard IDL demo on each shows the Power Mac
> running the demo ~40% slower. The Sparc LX did not page or swap during the
> tests.
> ------------------------------------------------------------ --------------
> Jeffrey Bloch Office: (505) 665-2568
> Astrophysics and Radiation Measurements Group ALEXIS Soc: (505) 665-5975
> Los Alamos National Laboratory FAX: (505) 665-4414
> Group NIS-2, Mail Stop D436 e-mail: jbloch@lanl.gov
> Los Alamos, NM 87545
> ------------------------------------------------------------ --------------
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| Re: Impressions of IDL on PowerMac vs. Sparc [message #3630 is a reply to message #3535] |
Thu, 09 February 1995 11:05 |
gurman
Messages: 82
Registered: August 1992
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Member |
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In article <walsteyn.791758364@ruund3.fys.ruu.nl>, walsteyn@fys.ruu.nl
(Fred Walsteijn) wrote:
> In <Pine.CVX.3.90.950131111953.24952A-100000@sstcx1.lanl.gov> Jeff Bloch
<jbloch@sstcx1.lanl.gov> writes:
>
>
>> We have just started playing with IDL on a Power Mac (Quadra 650 with Power
>> Mac upgrade card, (6100/66 equivalent) with 40MB of memory) and comparing it
>> to IDL running on a Sparc LX. We have found some very interesting speed
>> differences. Simple large array operations are a factor of two FASTER on the
>> Power Mac than on the Sparc, yet transcendental function array operations
>> (sin, asin, tan, etc) appear to be a factor of two SLOWER on the Power Mac.
>
> You might get a higher speed on the PowerMac if you would install
> a new floating point math library (made by Apple). It's called MathLib.
> Ask or read about it in a comp.sys.mac.* newsgroup. (I don't know the
> details as I don't have a PowerMac. The only thing I do know is that
> the MathLib in ROM is ``slow'' when it comes to transcendental functions...
> The software patch, i.e., the MathLib extension, solves the speed problem.)
>
> Good luck,
> Fred. (walsteyn@fys.ruu.nl)
Another determinant of speed in math-dependant operations on PowerMacs
is the presence (and size) of level 2 cache. Does the Apple upgrade card
come with an L2 cache card?
Joe Gurman
--
J.B. Gurman / Solar Physics Branch/ NASA Goddard Space Flight Center/
Greenbelt MD 20771 USA / gurman@uvsp.gsfc.nasa.gov
| Federal employees are still prohibited from holding opinions while|
| at work. Therefore, any opinions expressed herein are somebody |
| else's. |
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