The Jaguar uses 7 megawatts of power or 7 million watts. An exascale system that used CPU processing cores alone might take 2 gigawatts or two billion watts, says Dave Turek, IBM vice president of deep computing. "That's roughly the size of medium-sized nuclear power plant. That's an untenable proposition for the future," he said.
Estimates on the size of exascale systems range from 10 million to 100 million cores. Turek believes the latter number is more likely.
"We think exascale is a 100 million-core kind of enterprise, and there doesn't seem any real pathway around it, said Turek. "Where the players in pursuit of exascale are today is [at] a state of investigation to see what the right model is. So if hybridization is the key, then what is the ratio of special-purpose cores to conventional cores?" he said.
These future systems will have to use less memory per core and will need more memory bandwidth. Systems running 100 million cores will continually see core failures and the tools for dealing with them will have to be rethought "in a dramatic kind of way," said Turek.
IBM's design goal for an exascale system is to limit it to 20 megawatts of power and keep it at a size of between 70 and 80 racks. Jaguar is entirely built of CPUs, but Bland also sees future systems as hybrids, and points to chip development by both Intel and AMD that combine CPUs and co-processors.
"We believe that using accelerators is going to be absolutely critical to any strategy to getting to exaflop computers," he said.