Desktop multiprocessing: Not so fast

Some time ago, computer vendors passed the point of diminishing returns concerning processor clock speeds, and could no longer keep hiking frequency rates. To maintain continued performance improvements, suppliers turned to installing multiple instances of the processor -- multiple cores -- on a processor chip, and as a result, multicore processors are now mainstream for desktops. But to realize any performance improvements the software has to be able to use those multiple cores.

And to do that, most software will need to be rewritten.

"We have to reinvent computing, and get away from the fundamental premises we inherited from von Neumann," says Burton Smith, technical fellow at Microsoft Corp., referring to the theories of computer science pioneer John von Neumann (1903 - 1957). "He assumed one instruction would be executed at a time, and we are no longer even maintaining the appearance of one instruction at a time."

But software cannot always keep up with the advances in hardware, says Tom Halfhill, senior analyst for the Microprocessor Report newsletter in Scottsdale, Ariz. "If you have a task that cannot be parallelized and you are currently on a plateau of performance in a single-processor environment, you will not see that task getting significantly faster in the future."

http://www.computerworld.com/s/article/9136633/Desktop_multiprocessing_Not_so_fast?taxonomyId=12&pageNumber=1