Chapter 14: Support for Parallel Processing

Definition of Parallel Processing

SAS 9 supports a new wave of SAS functionality related to parallel processing. Parallel processing refers to processing that is handled by multiple CPUs simultaneously . This technology takes advantage of hardware that has multiple CPUs, called SMP machines , and provides performance gains for two types of SAS processes:

• threaded I/O

• threaded application processing.

SMP machines have multiple CPUs and an operating environment that can spawn and manage multiple pieces of executable code called threads . A thread is a single, independent flow of control through a program or within a process. Threading takes advantage of multiple CPUs by dividing processing among the available CPUs. A thread-enabled operating environment provides support for threads; for example, each thread needs a context (like a register set and a program counter), a segment of code to execute, and a piece of memory to use in the process.

Even if your site does not use an SMP machine, SAS 9 can still provide increased performance. Some types of threading can be performed using a single CPU.