[Q-e-developers] BG/Q: make.sys fine tuning to get better performances

[Carlo Cavazzoni]

Hi All,

I would like to share with you some
make.sys parameters that should improve the performance of the code:

1) use -D__LINUX_ESSL  instead of -D__FFTW (essl fft seems slightly better)
2) use -D__ELPA (elpa gives better performance and scalability with 
diagonalization at gamma)
DFLAGS         = -D__XLF -D__LINUX_ESSL -D__MASS -D__MPI -D__PARA 
-D__SCALAPACK -D__OPENMP -D__ELPA
FDFLAGS        = 
-D__XLF,-D__LINUX_ESSL,-D__MASS,-D__MPI,-D__PARA,-D__SCALAPACK,-D__OPENMP,-D__ELPA

3) link with /bgsys/drivers/ppcfloor/comm/xl.ndebug/bin/mpixlf90_r compiler
it links the version of the mpi library that do not contains the debug code
LD             = /bgsys/drivers/ppcfloor/comm/xl.ndebug/bin/mpixlf90_r

carlo

-- 
Ph.D. Carlo Cavazzoni
SuperComputing Applications and Innovation Department
CINECA - Via Magnanelli 6/3, 40033 Casalecchio di Reno (Bologna)
Tel: +39 051 6171411  Fax: +39 051 6132198
www.cineca.it