What is performance?
The performance of a software system can be broadly defined as:
The degree to which the system is able to meet its throughput and/or latency requirements in terms of the number of transactions per second or time taken for a single transaction.
We've already taken an overview of measuring performance in the introductory chapter. Performance can be measured either in terms of response time/latency or in terms of throughput. The former is the time it takes for the application to complete a request/response loop on average. The latter is the rate at which the system processes its input in terms of the number of requests or transactions successfully completed per minute.
The performance of a system is a function of its software and of its hardware capabilities. A badly written piece of software could still be made to perform better by scaling the hardware—for example, the amount of RAM.
Similarly, a piece of software can be made to work better on existing hardware...
