Subject: CCL:Beowulf+Chemistry web site

From: Harold W Schranz <[email-masked]>
Date: Mon, 18 Oct 1999 10:15:25 +1000

Interesting diversion from the main thread.

I would like to see hard evidence of the following "claims" of
Athlons/Pentiums vs PowerMacs G3/G4 (especially running Linux singly
or in clusters of workstations/CPU's).

Dr. Peter Burger wrote:  
> Eugene Leitl claimed:
> > Unfortunately, Athlons (700 MHz AMD Athlon has just been released) is
> > even faster than G4:
> > http://www.amd.com/products/cpg/athlon/benchmarks/specfp.html
>
> What do you mean by unfortunately - it's nice that they are so fast!!
> 
> Nevertheless has someone achieved to produce a handtuned dgemm version for
> the Athlon? Just like GOTO's dgemm version for the Alpha 21164?
> 
> Dgemm on the Athlon is not too bad though - using Clint Whaley's excellent
> Atlas library one obtains
> 
> 530-540 MFLOPs on a 500 MHz Athlon
> 
> That's still far off of the potentially accessible 1 GFlop though.

I would dearly like to see proof that the "Athlons" (or any Pentium)
is faster than the latest G4 machines. It is definitely not true at
the same clock rate.

As the celebrated Henry Rzepa mentioned, G3s have been used in clusters:
>Regarding parallel implementations of chemistry, has anyone heard of
>any chemical applications of the related "Appleseed Project"
>
>http://exodus.physics.ucla.edu/appleseed/appleseed.html

Since there are now a range of Linuxes (LinuxPPC, MkLinux, and others)
as well as OS X which is based on the Mach microkernel for the PowerMac
G3 and G4 platforms it would be nice to see some hard numbers as they
are worthy machines and, aside from runnning Linux, come with a decent
operating system. A Linux cluster (Beowulf or whatever) would be
interesting.

Apple claims a sustained 1 Gflop for the G4 chip with a theoretical
peak of 3.6 Gflops: (from http://www.apple.com/powermac/)

"The new PowerPC G4, architected by Apple, Motorola and IBM,
is the first microprocessor that can deliver a sustained
performance of over one gigaflop. In fact, it has a theoretical
peak performance of 3.6 gigaflops."

If true, G4 machines would make very nice platforms for running (some)
chemistry applications. The implementation and use of the vector
instructions are of most interest to me. Even so, I am also interested
in the performance of the usual 100*100 and 1000*1000 Linpack and
MDBNCH benchmarks (I dont care what anyone thinks about these benchmarks,
their scaling is useful for me to compare against my own codes).

For those interested, some links to pursue:
Linpack:http://performance.netlib.org/performance/html/PDStop.html
MDBNCH: http://www.sissa.it/furio/Mdbnch/results.txt

I am wondering what the relative computational strengths of a
Pentium/Athlon/clone running Linux would be against PowerMac G3/G4
platforms. Anybody got there hands on a real G4 box and run some
(especially the above) benchmarks?

Adios
Harry.

-- 
------------------------------------------------------------------------
Dr. Harold W. Schranz,            Office Ph.:         +61 (02) 6249 5988
Computational Chemist,            Dept Ph.:           +61 (02) 6249 3437
ANU Supercomputer Facility,       Fax:                +61 (02) 6279 8199
Australian National University,   Email:       [email-masked]
Canberra, ACT 0200, AUSTRALIA.    WWW:   http://anusf.anu.edu.au/~hws900
------------------------------------------------------------------------

---

From: Eugene Leitl <[email-masked]>
Date: Mon, 18 Oct 1999 00:32:17 -0700 (PDT)

> is faster than the latest G4 machines. It is definitely not true at
 
1) Athlons are not Pentiums. The architecture is entirely different,
   since designed by the Alpha AXP core developer.

2) Athlons are sure slower than G4s at the same clock rate, however no G4s
   with the same clock rate as Athlons are available (and won't be 
   available, because the Athlon core has been engineered to scale to 
   high frequencies (currently 700 Mhz) whereas PowerPC architecture
   has been not).
 
Athlons should be considerably more COTS (commodity off the shelf)
items than G4 (which are currently scarce, or so I heard).