Photograph by Veronika Hohenegger, The Leibniz Supercomputing Centre (LRZ).
SPPEXA
The SPPEXA team
Software for Exascale Computing Project Objectives
SPPEXA addresses fundamental research on various aspects of HPC software, which is particularly urgent against the background that we are currently entering the era of ubiquitous massive parallelism. This massive parallelism only will smooth the way for extreme computing up to exascale, i.e. computations with 1018 floating point operations per second, and the insight resulting from those simulations.
Project Funding
SPPEXA is funded by the German Research Foundation (DFG) (German Priority Programme 1648). Approximately €24 Million in total.
Project Partners
Racks and brains
SPPEXA involves more than 50 universities and research institutes in Germany, France, Japan and world-wide.
The age of exascale computing is coming, and dramatic increases in computational speed could lead to important scientific breakthroughs, yet software must also evolve in line with changes to the computing paradigm. The SPPEXA programme supports research into software for tomorrow’s computing environment, as Dr Benjamin Uekerman explains. The first exascale computer, capable of 1018 floating point operations (flops) a second, is expected to come into operation at some point around the mid-2020s. This dramatic increase in speed could lead to important breakthroughs across many areas of science, so a lot of resources have been invested in the race to develop the first exascale computer, yet less attention has been paid to the software required for this new computing environment. “People often forget that you also need funding to develop the software to run on these machines,” says Dr Benjamin Uekermann, SPPEXA Programme Manager. A priority programme funded by the German Research Foundation (DFG), the aim in SPPEXA is to develop software for this new computing paradigm. “With a new high-performance computing (HPC) architecture, different algorithms are required to improve simulation efficiency,” continues Dr Uekermann.
Computer simulations This research holds relevance to several scientific disciplines, from astro-physics to bioinformatics to climate change, with supercomputers commonly used to run many different types of simulations. Typically, when the people running such a simulation find that it is running too slowly, or they want to address a different problem, they
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ask supercomputing specialists to modify and improve the code, yet Dr Uekermann says this approach has its limitations. “You are only scratching the surface of where you can improve. Sometimes, you need to change more fundamental things to improve efficiency on such HPC systems,” he explains. The approach within the programme is more collaborative, bringing computing specialists together with researchers in specific applications. “We have joint projects with application people and mathematics specialists in HPC. They work together for six years and develop the application,” outlines Dr Uekermann.
era of massive parallelism, Dr Uekermann says certain things will change. “For example, we agree that there is a high probability that there will be single failing entities on a regular basis,” he says. If a single chip crashes, we cannot allow that to lead to the complete programme crashing. So we need software and algorithms that are capable of interfering with such situations. There are different ways of tackling this, the most elegant uses algorithms to resolve the problem.” This type of problem is among the six research directions being pursued within SPPEXA, which include computational algorithms, system software and
With a new high-performance computing architecture, different algorithms are required to
improve simulation efficiency. There are 17 projects within SPPEXA, focussing on different applications and areas of research, including astro-physics, plasma physics and fluid dynamics. More powerful computers allow researchers in these disciplines to include more data in simulations and so gain deeper insights into important questions, yet effective software is essential to realising these benefits. “With new machines you need new software,” points out Dr Uekermann. As computing enters the
programming. The other research directions are data management and exploration, and then application software, a set of priorities which reflects the complexity of exascale computing. “Different projects work on different layers that we need for software. So there are projects that work on very low levels, where it’s really about the systems software. For example, there’s one project in SPPEXA that is developing a file system that can work on an exascale machine,” says Dr Uekermann.
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Other projects within SPPEXA look at higher levels, where computer scientists work in close collaboration with application specialists to develop new algorithms. “In order to tackle the problem, you have to work with all these layers, to make them ready for exascale computing,” stresses Dr Uekermann. The various projects in SPPEXA differ quite significantly in some respects however, with some taking an evolutionary approach, while others are more revolutionary. In the former case, Dr Uekermann says the focus may be on something quite low-risk. “This could be a software feature that is quite low-risk, but which has to be ported to exascale, so that it is ready by the time exascale machines are available,” he explains. Other projects however are more high-risk, where scientists try to revolutionise certain application domains, for example by changing the basic principles behind simulations. “There is more risk behind this type of project. If it works out, then many codes will have to rewritten, to be ported to a new programming paradigm. But it would also have a much bigger impact,” continues Dr Uekermann. “We have ported many applications and made them ready for Exascale computing. We have been working on existing codes with existing communities.” A lot of progress has also been made in the more revolutionary projects, with the development of prototypes which show that certain things can be dramatically improved with the development of new techniques. The focus within SPPEXA is on software for exascale computers, yet Dr Uekermann says the project’s research also holds implications for today’s machines. “The vast majority of the things that we have developed will run on today’s supercomputers. But they have been built in a way that would allow them
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to be transferred to the next generation of machines,” he outlines. The most powerful supercomputer in the world currently is Summit, which has a performance of 122.3 petaflops (a petaflop=1015 floating point operations a second). The most powerful machine in Germany meanwhile is the recently set up SuperMUC-NG, based at the Leibnitz Supercomputing Centre near Munich, which has a peak performance of 26.9 PFLop/s. These machines are already capable of dealing with huge volumes of data, yet an exascale machine would represent a dramatic step forward on even these levels of performance. While the point at which such a machine will be developed is difficult to predict, it is moving closer. “The point at which an exascale computer will be developed is difficult to precisely forecast, but it’s not far away in terms of the science,” says Dr Uekermann. This underlines the importance of continued research into software for exascale computers, and for supercomputers more generally. While the SPPEXA programme itself cannot be extended beyond its current term, Dr Uekermann hopes that research will continue. “We are working hard to convince funding bodies that there is a long-term need to develop software for HPC machines,” he says. Many of the projects in the second phase of SPPEXA brought together researchers from different countries, which could form the basis for further investigation, while Dr Uekermann says there is also the possibility of wider collaborations in future. “We have worked together with the French and Japanese funding agencies, to look at co-funding international projects. This has turned out to be really valuable, because we can bring together people with different backgrounds and share expertise,” he outlines.
Contact Details
Project Manager, Dr. Benjamin Uekermann Technische Universität München Institut für Informatik Boltzmannstraße 3, 85748 Garching bei München T: +49 89 289 18600 E: uekerman@in.tum.de W: www.sppexa.de W: https://link.springer.com/ book/10.1007/978-3-319-40528-5
Benjamin Uekermann
Benjamin Uekermann studied Applied Mathematics and Computer Science at the Technical University of Munich. Since receiving his PhD in 2016, he works as project manager of SPPEXA. His research focuses on software development for multi-physics simulations. He is currently one of the main developers of the coupling library preCICE.
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