“Straatsma says that with 90% of the floating point value coming from high core-count GPUs, all applications will need to adopt them into their codes.”

This represents a very unsettling aspect of going into exascale–the gap between accessible computing (the 99% of HPC users) and leadership-scale computing is going to expand to a point where users are either on the wagon or they’re not. There will be no middle ground.

What happens to the vast majority of HPC users who are using codes that aren’t backed by dedicated scientific software developers? Will they simply be stuck at a performance level where die shrinks stopped being physically possible?

And considering the fact that only ~50% of Titan’s current load even uses GPUs even after extensive application readiness programs and training by ORNL, what happens to the other 50% of cycles when Summit replaces Titan? Ideally some of the “lost” 50% will be brought on the wagon by these new application readiness efforts, but will the remainder be left out in the cold and told to look elsewhere?