Performance Testing is done to gauge and find a proper estimate of the performance of a system. The system here can be a computer, microcontroller, high speed server, network, etc .For instance, performance testing tools when applied to a microcontroller give a close estimate of the performance of the microcontroller in terms of MIPS (Million Instructions per second).This term gives an idea on how efficient and fast the microcontroller can perform. Performance testing also enables a comparative study of the system (system can be based on different platforms) on the basis of speed, reliability, efficiency, throughput, etc.

This can be helpful in selecting the right kind of methods for developing an application. Performance testing tools are basically diagnostic tools which aid in testing the effectiveness of a system. For instance, if the performance of a website is to be measured using these tools, they help in providing an understanding of the scalability of the website in the environment of third party products such as servers and middleware. Before using these tools, one needs to understand the content of the system under scrutiny and find ways to begin with. There are a number of performance testing tools available. A few have been mentioned here.

1) Ants Profiler: This tool works on the .NET framework. It determines the performance of an application which is written in any of the languages available on this framework. It gives a complete list of the slowest running codes, inefficient methods used and the time taken to execute each line of code. This helps to identify the bottlenecks present in the application and provide methods to optimize the system.

2) Open STA: This tool is based on CORBA (Common Object Request Broker Architecture).It allows a user to simulate heavy loads due to the activity of hundreds or thousands of virtual users. It provides a graphical view of the user response time and the resources utilized. One can test all kinds of web servers and application servers.

3) Apache J meter: A desktop java application designed to test the performance of static and dynamic resources such as java objects, databases, Perl scripts, FTP servers; etc .This tool operates by simulating heavy loads on a server or a system and then analyzing it by measuring its performance under different load conditions.

In simple terms, these tools evaluate a system to identify its usability problems and also find its success rate among its competitors.