Recognizing a Processor Bottleneck

Bottlenecks occur only when the processor is so busy that it cannot respond to requests for time. These situations are indicated, in part, by high rates of processor activity, but mainly by long, sustained queues and poor application response. If you don't have a long queue, you have a busy processor, but not a problem.

If you notice sustained high processor use and persistent, long queues:

• Rule out a memory bottleneck. These are much more common than processor bottlenecks, especially or workstations and small point-to-point networks. For more information, see Chapter 12, "Detecting Memory Bottlenecks."

• Identify the processes using processor time. Determine if a single process or multiple processes are active during a bottleneck.

• Examine the processor-intensive processes in detail. Determine how many threads run in the process and watch the patterns of thread activity during a bottleneck. If you develop or maintain these processes, you can write counters to monitor thread activity at a lower level.

• Consider the priority at which the process and its threads run. You may be able to eliminate a bottleneck merely by adjusting the base priority of the process or the current priorities of its threads.

• Choose a solution and test it, then log the general activity of your system, using counters like those in the Overview settings file described in Chapter 10, "About Performance Monitor."