Slow speed after changing from serial to parallel (with ex2f.F)

Sanjay Govindjee gsanjay at ethz.ch
Wed Apr 16 09:27:33 CDT 2008



>>
>> Also, with a smart enough LSF scheduler, I will be assured of getting 
>> separate processors ie 1 core from each different processor instead 
>> of 2-4 cores from just 1 processor. In that case, if I use 1 core 
>> from processor A and 1 core from processor B, I should be able to get 
>> a decent speedup of more than 1, is that so?
>
>  

You still need to be careful with the hardware you choose. If the 
processor's live on the same motherboard then you still need to make 
sure that
they each have their own memory bus. Otherwise you will still face 
memory bottlenecks as each single core, from the different processors, 
fights for bandwidth on the bus. It all
depends on the memory bus architecture of your system. In this regard, I 
recommend staying away from Intel style systems.  -sg





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