FZJ-ZAM Blue Gene/L User Information

Running a sample program

Notes

(extract from IBM Redbook

Unfolding IBM eServer Blue Gene Solution )

The IBM XL compilers are available for applications written in FORTRAN, C, and C++. Most of the XL compiler options on Blue Gene/L are the same as options on other IBM platforms.

The XL compilers for Blue Gene/L have been customized for the runtime environment of the compute nodes. These customized versions are available on the JUBL login node and are named blrts_xxx.

Sample Program

A sample program written in C is available on the JUBL system under

/bgl/local/samples/helloworld/helloworld.c

A sample Makefile for this application is also available as

/bgl/local/samples/helloworld/Makefile

and looks like:

#####################################################################
#                                                                   #
#      (c) COPYRIGHT IBM CORP. 2001, 2005 ALL RIGHTS RESERVED.      #
#                                                                   #
#                LICENSED MATERIALS-PROPERTY OF IBM.                #
#                                                                   #
#####################################################################

BGLSYS = /bgl/BlueLight/ppcfloor/bglsys

CC = /usr/bin/blrts_xlc
CPPC = /usr/bin/blrts_xlc
FC = /usr/bin/blrts_xlf90

# try -qarch=440 first, then use -qarch=440d for 2nd FPU later on
#  (SIMDization requires at least -O3)
# use -qlist -qsource with 440d and look for Parallel ASM instructions.
#
CFLAGS= -O3 -g -I$(BGLSYS)/include -L$(BGLSYS)/lib -qarch=440 -qtune=440
FFLAGS= -O3 -g -I$(BGLSYS)/include -L$(BGLSYS)/lib -qarch=440 -qtune=440
#
LIBS_MPI = -lmpich.rts -lmsglayer.rts -lrts.rts -ldevices.rts
LIBSF_MPI = -lmpich.rts -lfmpich.rts -lmsglayer.rts -lrts.rts -ldevices.rts

default: helloworld.rts

helloworld.rts:   helloworld.o
          $(CC) $(CFLAGS) -o helloworld.rts helloworld.o $(LIBS_MPI)

helloworld.o:   helloworld.c Makefile

clean::
        rm -rf *.o  *~ *core*
        rm -rf *.rts

The program can be started with:

llrun -np 32 -verbose 1 -exe `/bin/pwd`/helloworld.rts -cwd `/bin/pwd`

For help:

llrun -h