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Old   June 19, 2009, 14:12
Default Parallel Efficiency
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Christophe Kassiotis
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Hello everybody,

I want to measure the efficiency of the paralleling for different mesh sizes. My problem is quite simple: a flow in a tube divided in 6 domains by METIS (the 6 processor are on the same machine). It is quite surprising for me to see that when one augments the refinement, the efficiency decreases after an optimum. I was thinking that the efficiency increases in such a case.

The efficiency is here measured as: TCPU(1) / ( 6 * TCPU(6) ), where TCPU(N) is the CPU time for parallel computations on N processors.

I thought first it was linked to the fieldTransfer=1 (fieldTransfer are inverted on the attached graph), so I change it. The results are a little closer to what expected, but I still observe the general behavior depicted above. Finally, maybe are my results normal, but I have no explanation for them. What do you think about this ?

Thank you,

Attached Images
File Type: jpg para8mesh.jpg (95.4 KB, 22 views)
File Type: png efficiencyVsMesh.png (4.2 KB, 33 views)

Last edited by kassiotis; June 22, 2009 at 04:39. Reason: Add precision, correct english mistakes
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