On our little cluster (12 nodes, 144 cores) I have installed the new Intel Cluster Studio (ICS) 2011. I don't have uninstall Intel Cluster Toolkit (ICT) 2010. All of our programs (Fortran or C++ codes) are 15% slower when we start them with the mpirun of ICS 2011. I don't understand why... I did a normal installation and I didn't noticed any problem during the installation. I did the ICS 2011 installation with the same method that I used for ICT 2010.
About our Hardware/Sofwares:
Master: Intel Xeon CPU E5620
nodes: Intel Xeon CPU X5650
OS: CentOS 5.5
we are using Infiniband DDR (driver OFED-1.5.1); I_MPI_FABRIC set to shm:ofa; pinning is disabled.
We have recompiled our programs with Intel 12.0 or Intel 11.1 Compilers and the problem appears in the both case...so it is not a compiler problem.
What can I do ?