SMP workloads

The effect of additional processors on performance is dominated by certain characteristics of the specific workload being handled. This section discusses those critical characteristics and their effects.

The following terms are used to describe the extent to which an existing program has been modified, or a new program designed, to operate in an SMP environment:

SMP safe

Avoidance in a program of any action, such as unserialized access to shared data, that would cause functional problems in an SMP environment. This term, when used alone, usually refers to a program that has undergone only the minimum changes necessary for correct functioning in an SMP environment.

SMP efficient

Avoidance in a program of any action that would cause functional or performance problems in an SMP environment. A program that is described as SMP-efficient is SMP-safe as well. An SMP-efficient program has usually undergone additional changes to minimize incipient bottlenecks.

SMP exploiting

Adding features to a program that are specifically intended to make effective use of an SMP environment, such as multithreading. A program that is described as SMP-exploiting is generally assumed to be SMP-safe and SMP-efficient as well.