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-   -   OpenFOAM compiled with Intel C++ Compiler? (http://www.cfd-online.com/Forums/openfoam-solving/65017-openfoam-compiled-intel-c-compiler.html)

af631717 June 1, 2009 12:50

OpenFOAM compiled with Intel C++ Compiler?
 
Hi,
has anybody compiled OpenFOAM with the Intel Compiler and has compared the difference of the performance for a specific solver?
Especially with the new Intel Nehalem architecture should be a significant speedup.

Regards
Achim

bjj June 5, 2009 05:24

Achim,
As part of a benchmark test series for parallel computing we made a dambreak test case with icoFoam on the Intel Nehalem processor (on up to 32 cores). We tried to compile with both Gcc and Icc. In general we reduced the computational time with about 15% when using Icc.

Regards,
Bjarne

af631717 June 5, 2009 06:19

OpenFOAM compiled with Intel C++ Compiler?
 
Bjarne,

thanks for this information. It is about what I expected and mean, that it is sometimes better to buy a good compiler for 500 Euro than buy a new hardware.

How long did the calculation take for n iterations? Is the orig. tutorial case not to small for 32 cores?

Is it an advantage to use HyperThreading with the Nehalem? And use 64 "theoretical" cores?

Regards
Achim

af631717 June 5, 2009 06:32

OpenFOAM compiled with Intel C++ Compiler?
 
Was it difficult to compile OF with the intel compiler?
Achim

bjj June 5, 2009 06:41

With the Nehalem tests we had a run time on 1 core at 3350s while the run time on 32 cores were 170s. So a speed-up at about 19-20 on 32 cores.

The original tutorial case is to small for a test on 32 cores. We used a maximum at 4M computational point.

We did not use HyperThreading in this test so I can't say if this is an advantage here.

Regarding the compilation the switch from Gcc to Icc is fairly straight forward. Edit the compiler settings in your etc/bashrc-file.

Regards,
Bjarne


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