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guide:dell [2012/03/02 17:04]
kevin
guide:dell [2012/03/02 17:10] (current)
kevin
Line 57: Line 57:
   * customisations should appear in the files //after// the above sections   * customisations should appear in the files //after// the above sections
   * customisations should //not overwrite// settings to ''​PATH''​ or ''​LD_LIBRARY_PATH''​ but should //append or prepend// to them instead.   * customisations should //not overwrite// settings to ''​PATH''​ or ''​LD_LIBRARY_PATH''​ but should //append or prepend// to them instead.
 +
 +
 +=====Code Development=====
 +
 +To ensure compatibility of user code with the Dell nodes it is recommended that binaries intended to run on these are recompiled in the target environment. To this end, one node has been configured as a new login node: ''​dell-login01''​.
 +Users should login to ''​dell-login01''​ from one of the existing login nodes (''​login01'', ​ ''​login02''​) using ssh, as in:
 +
 +  ssh dell-login01
 +
 +Standard linux utilities and the GCC compilers are available on this node, but the Intel compilers 12.0 and Intel MPI are already loaded into the environment by the ''​dell/​default-environment''​ module. It is recommended to compile code using the Intel compilers (''​icc''​ and ''​ifort''​) for best performance. E.g.
 +
 +  icc -O3 -ip -xHOST -lmkl_intel_lp64 -lmkl_intel_thread -lmkl_core -liomp5 -lpthread prog.c -o prog
 +
 +where we are also dynamically linking the Intel MKL library (also recommended). Note that for MPI code, the above would become:
 +
 +  mpicc -O3 -ip -xHOST -lmkl_intel_lp64 -lmkl_intel_thread -lmkl_core -liomp5 -lpthread prog.c -o prog
 +
 +or using ''​ifort''​ or ''​mpif90''​ for serial or MPI codes, repectively.
 +
 +Note that the ''​-xHOST''​ flag will optimise the binary for the same type of CPU on which the compilation is taking place. Since ''​dell-login01''​ is identical in terms of hardware to the Dell compute nodes, that is appropriate here. In practice, the same binary should be compatible with the CPUs on other nodes as long as they are Intel Westmere or Nehalem CPUs (but not Harpertown which has a different microarchitecture). However the program may still fail on other node types for reasons of library incompatibility if the Linux distribution differs.
  
/var/www/wiki/data/pages/guide/dell.txt · Last modified: 2012/03/02 17:10 by kevin