Using Multiprocessors Efficiently

Typically, applications that express concurrency requirements with threads need not take into account the number of available processors. The performance of the application improves transparently with additional processors because the operating system takes care of scheduling threads for the number of processors that are available. When multicore processors and multithreaded processors are available, a multithreaded application's performance scales appropriately because the cores and threads are viewed by the OS as processors.

Numerical algorithms and numerical applications with a high degree of parallelism, such as matrix multiplications, can run much faster when implemented with threads on a multiprocessor.

In this manual, whenever multiprocessors are discussed, the context applies also to multicore and multithreaded processors unless noted otherwise.