[2010] Facing the Exascale Energy Wall

A recent report focused on the technical challengesin advancing from today's "petascale" systems to "exascale."Power, or more accurately energy, was a dominant challenge. This paper briefly reviews the energy challenge for exascaled sized systems, with an emphasis on the relatively enormous energy costs of referencing operands from the memory hierarchy. Then, usinga key step from the LINPACK benchmark, we investigate twodifferent approaches to reducing such costs: one which migratescomputations up from the host to higher levels of the hierarchy,and another in moving the whole computation closer to memory. Both show significant improvements over architecture as usual.