September 14, 2009, 6:28 am
Apple has opened the source code of Grand Central Dispatch (GCD), a powerful, system-wide concurrency framework that was introduced in Mac OS X 10.6. The userspace library component of GCD, which is called libdispatch, is now available for download under the terms of the Apache Software License. This will potentially make it possible, though not necessarily easy, for the feature to be adapted for use on other platforms. The source code of Apple's kernel-level GCD optimizations is also available as part of the XNU source tree, but the documentation indicates that kernel changes may not necessarily be required.
Our own John Siracusa's epic Snow Leopard review describes GCD in exhaustive depth so I'll spare you all of the details here. It provides an efficient system-wide threadpool and some high-level programming constructs that vastly simplify parallelization for application developers.