3 ms·

I'm glad Exacycle exists, but the tasks at which it excels are indeed not tasks for which supercomputers are usually employed. The things that are easy for a P

by stonogo 11y ago

I'm glad Exacycle exists, but the tasks at which it excels are indeed not tasks for which supercomputers are usually employed. The things that are easy for a PI to pay for with Visa are generally not the things that are interesting to do with supercomputers. I see where you're coming from with the DOE stuff, though; those guys are all about high-visibility "status" computing, and I don't really find that scene appealing either. I'm not sure what you consider a supercomputer, if you don't consider a petaflops machine with a 3PB filesystem and >50Gb/s i/o "supercomputing." I guess we'll just have to disagree.

dekhn 11y ago
I used to work for NERSC when they ran Seaborg. Before that, i ran my PhD simulations on the T3E Mjolnir (PSC) and the other one, at SDSC whose name I forget. Back in those days, those were supercomputers, but a single cloud machine replaces one of those now. The only thing I consider a supercomputer is a device designed for capability computing where the capability is ability to run codes that exhibit strong scaling due to their interconnect. The petaflops you quote are calculated by the strong scaling of LINPACK due to its design. I think you need a large amount of petaflops these days to really be considered a supercomputer. And those petaflops come from having a combination of low latency and high bandwidth-- you couldn't just point at Exacycle and say "that's a supercomputer". The 3PB filesystem and 50Gb/s IO (you didn't say if that was per-node, or the bisection bandwidth of the central switch, or what) aren't particularly "super". In some sense this is just arguing about the definition of a supercomputer which isn't super interesting; I have a preconceived notion of what one is. If Amazon put a bunch of machines on an MPI switch (IIRC they actually have) and scored well in Top500, and you could buy time on it, and it scaled your code, they'd have one too.

by stonogo 11y ago

dekhn 11y ago

I used to work for NERSC when they ran Seaborg. Before that, i ran my PhD simulations on the T3E Mjolnir (PSC) and the other one, at SDSC whose name I forget. Back in those days, those were supercomputers, but a single cloud machine replaces one of those now. The only thing I consider a supercomputer is a device designed for capability computing where the capability is ability to run codes that exhibit strong scaling due to their interconnect. The petaflops you quote are calculated by the strong scaling of LINPACK due to its design. I think you need a large amount of petaflops these days to really be considered a supercomputer. And those petaflops come from having a combination of low latency and high bandwidth-- you couldn't just point at Exacycle and say "that's a supercomputer". The 3PB filesystem and 50Gb/s IO (you didn't say if that was per-node, or the bisection bandwidth of the central switch, or what) aren't particularly "super". In some sense this is just arguing about the definition of a supercomputer which isn't super interesting; I have a preconceived notion of what one is. If Amazon put a bunch of machines on an MPI switch (IIRC they actually have) and scored well in Top500, and you could buy time on it, and it scaled your code, they'd have one too.