Softly Complementing the Machine
RWT: How is CXFS different from other file systems, and what makes it uniquely suited for the Altix?
Jason: CXFS or clustered XFS, is SGI’s distributed-shared file system. I want to first mention that there is nothing about CXFS per se that makes it unique to Altix, in fact CXFS supports heterogeneous file access to a wide-variety of operating systems including IRIX, AIX, HP-UX, 32-bit and 64-bit Linux, Solaris, MacOS, and Windows. The unique capability of CXFS is the seamless file sharing it enables. Unlike traditional SAN file systems, CXFS allows administrators to share a single volume with all attached systems. This is a benefit because it means that you don’t have replicated data specific to each server nor do you need to spend hours-transferring data between volumes. But the real benefit for Altix and HPC computer users is that it allows for the rapid sharing and analysis of output files, which can be terabytes in size. By shortening the time it takes to complete computation, analysis, and visual analysis CXFS combined with scalable systems can enable better science purely by enabling more cycles to be completed in a given period of time.
RWT: Do most Altix users compile with Intel’s compiler or do you find many using GCC?
Jason: I think most of our users are using both as appropriate. For their high-performance computing applications I believe they primarily use the Intel compilers, but for many open source utilities GCC is the right choice for recompilation. The Intel compilers have just proven better than GCC for parallel applications, although there is still room for improvement in both sets of tools.
RWT: Are there any features you would like to see added to the compilers you are using?
Jason: We work closely with Intel to give feedback on improving the compilers for large-scale systems, and Intel has been very receptive to our input. Our focus has been on using SGI’s depth of experience to help Intel enhance compiler performance on parallel applications and OpenMP codes. SGI has established a strong dialogue between our applications engineers and core-engineering teams regarding areas where the compilers and tools can continue to improve for scalable parallel performance. Our experience with the MIPSpro compilers used on IRIX and our extensive experience on large Origin systems has really allowed us to offer some unique expertise to the development process.
RWT: Does NASA employ any optimization techniques for their software (PGO, etc.)?
Jason: NASA Ames research center has developed a programming technique called Multi-Level Parallelism (MLP). MLP seeks to optimize an applications performance by synchronizing completion of all threads / processes of a particular job to reduce wait times. The result is increased efficiency for the overall computation. The benefits of this technique are particularly pronounced on very large systems: in a 512P system a 10% efficiency loss is equivalent to losing 51 processors of computing power which can get expensive very quickly.
RWT: Obviously, there is still a need for large SMP systems, what types of problems do you see such systems addressing?
Jason: SGI customers with large Altix systems are researching a wide variety of fields. The COMOS project at Cambridge University, led by Professor Stephen Hawking is using an Altix to research the origins of the universe. Climate modeling, weather forecasting, oil field yield optimization and exploration, vehicle manufacturing, earthquake research, homeland security are just a few areas I can think of but there are many more. It really is one of the most fascinating areas of computer science today and my hope is that the capabilities of Altix and the rapid adoption of Linux will create some amazing new breakthroughs that will change our lives. I think the history of computing has shown that the research being done on these types of systems has always generated scientific discoveries that are later adopted by a majority of users.
RWT: What industries are you seeing a lot of interest in the Altix systems from?
Jason: SGI focuses on five market areas for our products energy, manufacturing, government and defense, media, and sciences. We are seeing interest from each of these areas and have already placed Altix systems in all of them.