Blog: Multicore May Not Be So Scary [dealing with the issue: ...at a certain point, adding more cores slowed the system down instead of speeding it up.]

Multicore May Not Be So Scary
MIT News (09/30/10) Larry Hardesty

Massachusetts Institute of Technology (MIT) researchers built a system consisting of eight six-core chips that can simulate the performance of a 48-core chip, as a way to test if adding more cores continues to boost computing performance. The researchers tested several applications on their model, activating the 48 cores one by one and observing the results. The researchers found that at a certain point, adding more cores slowed the system down instead of speeding it up. However, slightly rewriting the Linux code so that each core kept a local count greatly improved the system's overall performance. "There's a bunch of interesting research to be done on building better tools to help programmers pinpoint where the problem is," says MIT professor Frans Kaashoek. "The big question in the community is, as the number of cores on a processor goes up, will we have to completely rethink how we build operating systems," says University of Wisconsin professor Remzi Arpaci-Dusseau.

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