Setting performance objectives

Performance objectives often consist of a throughput rate plus a list of dialog or batch functions and expected timings for each. Ideally, through them, good performance can be easily recognized and you know when to stop further tuning. So they must be:

• Practically measurable
• Based on a realistic workload
• Within the budget.

Such objectives might be defined in terms such as:

• Desired or acceptable response times, for example, within which 90% of all responses occur.
• Average or peak number of controlled operations through the system.
• System availability, including mean time to failure, and recovery after a failure.