Performance modeling and interim computing systems

The Blue Waters project faces an interesting challenge: The IBM POWER7 hardware on which the sustained-petaflop supercomputer will be based does not exist yet. The goal is to ensure many science applications can immediately take advantage of the full power of Blue Waters rather than the traditional method of spending six to 18 months porting and tuning code once a new system arrives. Because there is much application development work and other research to be done in preparation for Blue Waters and other future systems, NCSA has installed four systems to help with these critical tasks.

These systems are available to project team members and collaborators who are working on application development, system software enhancement, and education projects for Blue Waters. This work includes modeling single-chip performance, full-system performance, and performance of the networks and interconnects that bring together Blue Waters' hundreds of thousands of processors.

It also includes the development of scientific applications and system software that will run on Blue Waters—identifying bottlenecks, tuning mathematical libraries, reorganizing data structures, improving communication protocols, and optimizing applications to increase their performance.

An IBM POWER575+ cluster named BluePrint serves as a testbed where NCSA can validate the performance of compilers, the development environment, monitoring and management tools, and other elements of the software environment that IBM will provide for Blue Waters. BluePrint is composed of 120 POWER5+ nodes, each having 16 cores and 64 GB of memory. The AIX operating system and GPFS are installed, with Linux to be available for specific projects.

IBM POWER6 systems are an important part of the development of the Blue Waters archival storage environment and are also being used as a platform for application development. The Petascale Application Collaboration Teams (PACTs) are using the POWER6 platform for development and testing.

Another important tool is the IBM system simulator environment called Mambo. This software, which runs on an x86-compatible system, allows the Blue Waters team to simulate the performance of the POWER7 processor. This sneak peak at the Blue Waters' processor is essential to understanding how codes must be adjusted to use the architecture most effectively.

For more information on using the Blue Waters interim systems and receiving application development support, contact the Blue Waters Consulting Office at bwconsult@ncsa.illinois.edu.