Do you get MPI ping-pong latencies on the order of a microsecond on a "normal" public cloud?
No? Well, MPI applications that are sensitive to latency is one usecase where a "real" supercomputer can be useful.
No? Well, MPI applications that are sensitive to latency is one usecase where a "real" supercomputer can be useful.
http://icl.cs.utk.edu/hpcc/hpcc_results_lat_band.cgi
I do believe I get it. Now to find out what kind of applications are greatly benefited from this.
Thanks HN! You always make me dig in and learn new things!
Edit: It was "MPI latency" that led me to that result, by the way.
The common applications are scientific computing usually, here's a quick overview[1] of the kind of algorithms ran on supercomputers: PDEs, ODEs, FFTs, Sparse and Dense linear algebra, etc.
These are usually used for scientific applications like weather forecasting, where you need to know about the result on time (i.e. before the hurricane reaches the coast!)
I look forward to reading the book.
Certainly it's true that ethernet has stepped up the game in recent years, while at the same time IB has more or less become a single-vendor play. So it'll be interesting to see what the future holds.
Further, proprietary supercomputer networks have things like adaptive non-minimal routing, which enables efficient use of network topologies that are more affordable at scale, such as flattened butterfly, dragonfly etc. AFAIK neither IB nor ETH + IP-level ECMP support anything like that.