Our company has developed an AIX application which does image
processing for satellite data. It uses approx. 512 MB of memory to run.
It has been developed on an RS/6000 workstation (a 43P), and shall
then run on a SP2 node after. We had no problem in porting RS/6000 =>
SP2, except for performance:
The published benchmarks (SPECInt and the like) of the 2 machines
roughly say that an SP2 node is twice as fast for real computations
and twice as slow for integer computations. Our application uses both,
maybe more integer numbers, hence we expected as worse case a twofold
loss in performance on the SP2.
The actual results are very different: the SP2 is 5-6 times slower
as the RS/6000, with a similar memory configuration.
Does anybody have had a similar experience? Other benchmarks, or
even a rule of thumb?
One possible explanation we heard: the SP2 has no level-2 cache. Any
Thanks in advance for even the slightest information....