A new simulation by Sandia for the U.S. Department of Energy’s National Nuclear Security Administration has found that trying to use too many cores for multicore supercomputing processing just leads to slower, not faster, computations. Sandia is a multiprogram laboratory operated by Sandia Corp., a Lockheed Martin company. Using algorithms for deriving knowledge from large data sets, Sandia simulations found a significant increase in speed going from two to four multicores, but an insignificant increase from four to eight multicores.
Certainly, the memory wall is the biggest hardware threat to multicore. The idea that somehow 8 cores is the limit and that no progress is being made on memory bandwidth is misleading, however. Memory bandwidth is increasing, just not at the rate of Moore's Law. We can expect DDR3 and other technologies to help out.
The biggest threat to multicore overall, however, is the difficulty of parallel programming. Fortunately, there are new multicore programming technologies that have started to address that need. See, for example, www.cilk.com.
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Scientists Find Too Many Cooks - er, Cores - Spoils the CPU
Posted by: Chris Maxcer January 15, 2009 02:42 PMA new simulation by Sandia for the U.S. Department of Energy’s National Nuclear Security Administration has found that trying to use too many cores for multicore supercomputing processing just leads to slower, not faster, computations. Sandia is a multiprogram laboratory operated by Sandia Corp., a Lockheed Martin company. Using algorithms for deriving knowledge from large data sets, Sandia simulations found a significant increase in speed going from two to four multicores, but an insignificant increase from four to eight multicores.
The biggest threat to multicore overall, however, is the difficulty of parallel programming. Fortunately, there are new multicore programming technologies that have started to address that need. See, for example, www.cilk.com.