Execution time difference between Mac and IBM RISC/6000

Execution time difference between Mac and IBM RISC/6000

Post by Jeffrey Ung » Fri, 12 Mar 1993 03:59:17





>>floating point operations (but moderate memory and small i/o). The
>>RS/6000's are 2 to 4 times faster (at best). A Cray YMP achieves about
>[...]
>Once again, which RS/6000?  There is a substantial difference between
>a 220 and a 560...

A 320. You can take the speed difference to be about a
factor of 2 to 2.5. How much faster (and more expensive) are the fastest
RS/6000's?

Quote:>Also, what 3/486 system?  It's not really fair comparing a
>20-processor Sequent i386 system to an RS/6000.  :-)  

A bargain ba*t clone.

Quote:>If you mean an RS/6000 only outperforms a PC clone by a factor of 3,
>I'd guess that either your code was poorly written, you were using a
>very low-end PowerStation, or both.

You guess wrong! (and even a low end powerstation is a lot more
expensive than a cheap 486 clone). Apparently you did not
read the footnote regarding the code. It would be easy to make it
perform at higher mflops rates but then it would take *much* more time.
Since it vectorizes to the point of reaching 100 mflops on a Cray YMP,
I *doubt* it is poorly written! This rate qualifies for the "well-optimized"
designation.

Quote:>The quality of the compiler has a lot to do with this as well.  Even
>though I slagged on xlc in a previous post, it (and gcc for that
>matter) DO optimize code well, whereas I have no idea how good the f77
>compiler for the RS/6000 is.

This crunching *was* in C!

The RS/6000's are very good on certain kinds of number crunching, but
they don't exactly shine on a whole range of problems.

pju

 
 
 

Execution time difference between Mac and IBM RISC/6000

Post by samer Takri » Fri, 12 Mar 1993 22:43:34


All right guys, I am the one who first posted this question.
After many replies, I posted the following (which did not reach the net
for strange reasons):
I did not turn on the flags of generating a code that calls the Math
co-processor (on the Mac). After checking the MC boxes, the execution
time on the Mac dropped from 3 minutes to less than 15 sec. The IBM
RISC/6000 time was about 1 sec. This ratio 1/15 seems to be correct or
reasonable.
Thanks for many people who pointed that out for me.
-Samer

 
 
 

Execution time difference between Mac and IBM RISC/6000

Post by Pete Grego » Sat, 13 Mar 1993 08:37:39



>Also, what 3/486 system?  It's not really fair comparing a
>20-processor Sequent i386 system to an RS/6000.  :-)  

why not?  unless you explicitly write a program to multi-thread a task,
only ONE cpu will be used.  for a single-task benchmark on a sequent, one
CPU does practically the same as 20 or more.
--


UNIX System Admin.                Bangpath: ames!elroy!wvus!pete

 
 
 

1. FS: IBM RS/6000 Risc System/6000 SERVER POWERSTATION currently at $49.00

Please go to our webpage to see this and other great items that we have up for
auction on E-Bay.  Direct sales of items are also available.

http://WWW.JLAENTERPRISES.COM

Be sure to bookmark the page and check back weekly for many new items across
the board that will be added.  DO YOU HAVE ANYTHING THAT YOU NEED TODAY?  CALL
US AT (919) 844-0960 FOR DIRECT SALES.  We ship worldwide.

Thank You
JLA ENTERPRISES

WE BUY ANYTHING. CORPORATE ASSET RECOVERY/LIQUIDATION (AKA INVESTMENT
RECOVERY). SURPLUS, EXCESS INVENTORY, OVERSTOCK, OBSOLETE AND USED ITEMS. IF
YOU HAVE SOMETHING TO SELL GIVE US A CALL!!! SINGLE PIECE OR MULTIPLE
TRUCKLOADS. WE WILL PICK UP FROM ANYWHERE IN THE US (BY TRUCKLOAD ONLY).
CORPORATIONS OR INDIVIDUALS. CASH PAID FOR ALL ITEMS WITH NO HASSLE!!! (919)

If the web address above does not work, an alternate site is:

http://members.ebay.com/aboutme/jla_enterprises

2. PROBLEM with long file names using tar on a HP box !!!!

3. Inaccurate system clock on IBM RISC 6000

4. Parallel printing problems

5. VAX/SGI -> IBM RISC/6000 source format problem with FORTRAN code

6. DSL question

7. WTB: Microchannel ethernet card for IBM RS/6000 RISC Model 7013-520

8. savage4 migration from 3.3.6 4.0.2

9. IBM/6000 RISC WWW server

10. IBM RISC 6000 G-30

11. Linux on IBM RISC System/6000 F50?!

12. IBM Risc System 6000 results in the "Dongarra report"

13. No root login on a NEW IBM RISC 6000