[Beowulf] AMD64 results...

[Bill Broadley]

> ironically, icc -xW generates pretty good-for-opteron code,
> though of course, it's 32b.  I haven't tried using icc to
> generate em64t/and64 code.
> 
> regards, mark hahn.

Ah, got icc-8.1 to cooperate, dual 2.2 Ghz opteron+pc3200+2.4 kernel,
915.5MB array:
-O1
Function      Rate (MB/s)   Avg time     Min time     Max time
Copy:        2285.8039       0.2640       0.2800       0.3200
Scale:       2206.9798       0.2690       0.2900       0.3000
Add:         2341.5554       0.3740       0.4100       0.4200
Triad:       2181.9031       0.4060       0.4400       0.4800

-O2
Function      Rate (MB/s)   Avg time     Min time     Max time
Copy:        2370.4856       0.2570       0.2700       0.3400
Scale:       2285.8280       0.2670       0.2800       0.3400
Add:         2461.6513       0.3710       0.3900       0.4600
Triad:       2285.8229       0.3920       0.4200       0.5000

-O3 
Function      Rate (MB/s)   Avg time     Min time     Max time
Copy:        2461.5867       0.2730       0.2600       0.3400
Scale:       2370.4237       0.2910       0.2700       0.3500
Add:         2526.3684       0.4050       0.3800       0.4800
Triad:       2341.5151       0.4320       0.4100       0.5100

The strange thing is they are 32 bit binaries, despite being built
on a 64 bit os on a 64 bit hardware.

I played around with various mentioned optimizations (including -xW)
on the manpage, I never managed a 64 bit binary with icc-8.1 though.
The man page has numerous i32em and em64t references.




-- 
Bill Broadley
Computational Science and Engineering
UC Davis