I am curious whether Kathryn McKinley's Power Wall argument is measuring a first order or second order effect. (This argument is essentially a furthering of Google's cost per killowatt hour utility company perspective, which says that as a process becomes more parallel it becomes more power hungry.)
It was only 2002 when a paper was published about the significant benefits of using control theory to scale up the DTM package on a chip; previous methods used peak power as an approximation for controlling thermal dissipation. These heuristics also throttled EVERYHING down, not just say instruction prefetching. I guess what I am trying to say is, from an outsider's perspective, the trade off might simply be based on current engineering practice rather than long term trend. The other thing to note is that while compiler optimizations do play a role in power vs speed tradeoffs, higher level languages capable of describing transformations to themselves will play a bigger role. Sent from my Droid Charge on Verizon 4GLTE ------Original Message------ From: David Corking <[email protected]> To: "Fundamentals of New Computing" <[email protected]> Date: Tuesday, December 20, 2011 9:28:05 AM GMT+0000 Subject: Re: [fonc] History of computing talks at SJSU John Zabroski wrote: > We have also yet to put into practice languages which limit the client > run-time of an algorithm on a server (assuming the client can > parameterize over the server's service in some disciplined way). > > Solving this problem will eliminate virtually all IT jobs. Thanks for being provocative. In my turn, I think everything but your last sentence is correct. Google engineers have said that a key design parameter for their services is the cost of instructions in kilowatt-hours. So the problem may be less about idle cycles than about wasted cycles such as context switches, inefficient algorithms and compiler optimization. Meanwhile, I suspect servers for interactive services are rarely more than 90% idle. So I would suggest that efficient scheduling and request run-time limits are important economic and environmental problems to solve, but the solutions are unlikely to eliminate many digital tech jobs, as it is unlikely to benefit society by more than the equivalent of two Moore's law doubling cycles. That is a huge prize, but not the end of the world as we know it. My 2 farthings. David _______________________________________________ fonc mailing list [email protected] http://vpri.org/mailman/listinfo/fonc _______________________________________________ fonc mailing list [email protected] http://vpri.org/mailman/listinfo/fonc
