Table of contents

Quick links: redhat sles openmpi

Information and Trial Downloads

IBM Compilers

IBM XL C/C++ Version 9 and XL Fortran Version 11.1

• XL C/C++ Advanced Edition for Linux
• XL Fortran Advanced Edition for Linux

IBM XL C/C++ Advanced Edition Version 10.1 and XL Fortran Version 12.1

• XL C/C++ with (March 2009 update )
• XL Fortran with (March 2009 update)

IBM Rational Cafés

• C/C++ Café with discussions, documents, blogs and more

IBM Compilers observations

• IBM compilers are generally capable of better performance than the open-source gcc compilers (more advanced optimization techniques, specialized focus on the hardware platform)

• New IBM compiler versions for Linux on Power generally stay in sync with the IBM compiler versions for AIX

• IBM compilers generally have hardware-specific enhancements
  • If your application can be compiled for specific hardware targets and maximum optimization, improved performance gains can be achieved for that particular hardware system
  • For example, IBM compilers specifically support GPUL, Power 5 and Power 6 hardware

• IBM compilers support program directed feedback (PDF)

• Each new version of the IBM compilers incorporate many incremental fixes and improvements, many of which show improved performance
  • The IBM compilers are recommended for all benchmarking and high performance work
  • The latest versions include updates for the OpenMP processing directives which can also result in improved performance

Using XLC/XLF with openmpi

Here's an example script for using the XLC/XLF compilers with openmpi.

#!/bin/bash

compile_cmd="mpicc "
user=hpc

program=$1
cflags=$2
echo "xlc compile cflags" $cflags
export PATH=$PATH:/opt/ibmcmp/vac/10.1/bin:/opt/ibmcmp/xlf/12.1/bin:$PATH
export OMPI_CC=xlc
export OMPI_FC=xlf90_r
export OMPI_CFLAGS=-q64
export OMPI_FCFLAGS=-q64
export OMPI_LDFLAGS=-q64

echo "Compiling with: " $compile_cmd $program ${cflags} -q64 -L/usr/lib64/mpi/gcc/openmpi/lib64 /home/$user/${program}.c  -o /home/$user/${program} 

$compile_cmd ${cflags} -q64 -L/usr/lib64/mpi/gcc/openmpi/lib64 ${program}.c -o /home/$user/${program}

Related products

• ESSL for Linux on POWER available and often used in specialized HPC workloads where engineering and scientific performance improvements are needed.

• FDPR/Pro - Feedback Directed Program Restructuring (FDPR-Pro) is also available for performance improvements of executables. More information is available at this web site

IBM Compilers - XL C/C++ - Distro Support Summary

Latest updates for supported IBM C and C++ compilers

• XLC Ver 7

• XLC Ver 8
  • XL C/C++ Ver 8 RHEL 4 to RHEL 5 External Technote

• XLC Ver 9

• XLC Ver 10.1
• XLC Ver 10.1 PTF - Includes SLES 11 support

XL C/C++ example matrix of "support"

"This is not an official support page" Please be aware, we created this page as a handy but informal mapping of where and when the IBM compilers are expected to be supported. For official and formal support questions, please contact your IBM representative. Keep in mind that combinations listed in the tables below do not necessarily mean they've been tested by the performance teams.

• Supported: The product was announced at this distro level - install, build and run-time support provided

• Included: Installation, build and run-time environments should work just fine

• Binary Should Run: Binary compatibility is usually complicated.
  • For the tables below, this essentially simply says that the basic compiler was not updated to install and be able to build/compile/link executables on this distro base.
  • Binaries built on previous distro versions should run on the newer distro versions using the runtime libraries provided by the IBM Compiler product.
  • Binary compatibility is dependent on the associated distro rules, guidelines, and restrictions. No claims are being made here.

Red Hat RHEL support

The XL Fortran version level has historically been numbered two versions ahead of the corresponding XL C/C++ version. For example:

• XL C/C++ Ver 7 was released along-side XL Fortran Ver 9.1
• XL C/C++ Ver 8 was released along-side XL Fortran Ver 10.1
• XL C/C++ Ver 9 was released along-side XL Fortran Ver 11.1
• XL C/C++ Ver 10.1 was released along-side XL Fortran Ver 12.1

^{(1): While previously generated binaries "should" run, this is not intended to be a binary compatibility claim.}

For discussions or questions... To start a discussion or get a question about this table answered, consider posting on the Linux for Power Architecture forum.

Novell SuSE SLES Support

The XL Fortran version level has historically been numbered two versions ahead of the corresponding XL C/C++ version. For example:

• XL C/C++ Ver 7 was released along-side XL Fortran Ver 9.1
• XL C/C++ Ver 8 was released along-side XL Fortran Ver 10.1
• XL C/C++ Ver 9 was released along-side XL Fortran Ver 11.1
• XL C/C++ Ver 10.1 was released along-side XL Fortran Ver 12.1

^{(1): While previously generated binaries "should" run, this is not intended to be a binary compatibility claim.}

For discussions or questions... To start a discussion or get a question about this table answered, consider posting on the Linux for Power Architecture forum.