FAQ - Performance & Load Testing

[slinkanand]

Below is a list of Frequently Asked Questions in this forum. Please review these before posting a related question. If you have comments or suggestions on this FAQ, please either email me directly, or post to this thread. All (constructive) comments are welcome.

Definitions:

Performance Test – Often the “catch all” for all performance related types of testing. Often used in different ways by different people. Performance tests are normally interested in both “how much?” and “how fast?”

Load Test – Most commonly collects various performance related measurements based on tests that model varying loads and activities that the application is expected to encounter when delivered to real users. Often focuses on “how much” can the application handle.

Stress Test - Most commonly collects various performance related measurements based on tests that model varying loads and activities that are more “stressful” than the application is expected to encounter when delivered to real users. Sub categories may include:
- Spike testing (short burst of extreme load)
- Extreme load testing (load test with “too many” users)
- Hammer testing (hit it with everything you’ve got, often with no delays)

Volume Test – Any test focused on “how much” instead of “how fast”. Often related to database testing. The distinction between "volume" and "load" is that volume focuses on high volume and does not need to represent "real" usage.
· Performance Vs. Load Testing
· About the stress test
· Volume testing
· Difference between Load, Stress, and Performance
· Load-Stress_Stess-Load..A Confusion
· What’s the difference between Performance and Stress Testing????
· load, stress with scenario

Basics:

How do I get started with performance related testing?
· Basic concepts of performance/load testing
· Load test - - how to?
· Starting to performance test ... entrance criteria
· Load testing novice
· Total Newbie - Load Testing on a Budget

What skills does a Performance Tester/Engineer need to have?
· Skill set for a load tester
· Employers (see bottom half)
· Performance Testing (skills)

How do I determine/capture performance related requirements?
· What to look for in load testing
· Checklist for performance

Where can I find a sample performance test plan/test strategy document?
· Test plan for Performance Testing
· Formal document of how load testing will be structured
· Performance Test "Strategy" document
· Creating plans for Performance testing
· Load testing plan
· Test Plan for Load Testing
· Checklist for performance

Performance testing theory/methodology.
· Theory behind load/performance testing?
· Standard Methodology
· Performance test mehodology
· What my monitors tell me

Performance and Load Testing Tools:

Freeware/ShareWare/OpenSource Solutions:
· OpenSTA
· Microsoft Web Application Stress Tool (WAST)


Commercial Solutions:
· QALoad (Compuware)
· PerformanceStudio (Rational)
· SilkPerformer (Segue)
· LoadRunner (Mercury)
· Astra LoadTest (Mercury)
· e-Load (Empirix)
· WebLoad (Radview)
· Bean Test (Empirix)
· Microsoft Application Center Test (ACT)

How do I choose the right testing tool for me?
· Free load test tool for applications
· List of performance & load testing
· Load testing tools
· Looking for tool to simulate min. 60 users
· Cost effective performance tool
· Load testing tools
· Need to pick a performance tool
· Freeware load test tools
· Comparison of load test tools
· Looking for a integrated client server and web load test tool

Whats the difference between Virtual Users and Real/Physical/GUI Users?

Load Testing tools work at protocol level to generate the traffic/requests which would normally be generated by users driving the User Interface of your application.

These requests form the basis of a Load test script and in essence this is what is replayed by the ‘Virtual Users’ against the application/system under test.

Real/Physical/GUI Users are as the term suggest ‘real’ users using the GUI of your application to generate the requests against the application/system under test. However, in the scope of Load Testing these users are often simulated by using a functional/GUI testing tool to drive a ‘real GUI’ in order to capture the performance overhead/cost of the GUI as versus the protocol level requests generated by the Virtual Users.

In other words ‘real’ users interact with the application through input devices (mouse/keyboard). Virtual Users ‘intercept’ communications between the client computer and the application so the client aspect of the application is not actually invoked.

· What Performance testing tool does?


How do I model performance testing scenarios (what are concurrent users/virtual users)?
· Plausibility of users simulation
· Is Think Time necessary
· Time delay
· Concurrent Usage
· Number of Virtual Users
· Defining "Concurrent Use"
· Sizing
· # of concurrent users
· Estimating the number of users based on concurrent virutal users
· Actual vs. Virtual Concurrent users
· Need specifics on vusers to real...

How can performance of Application/System Under test be monitored?

All of the commercial tools offer monitoring capabilities to monitor metrics such as Network Resources, System Resources, Application Resources, Database Resources etc. Configuration and available metrics may differ from tool to tool, but should be covered in the documentation set provided with your software.

Other methods of monitoring resources during a Load Test are Windows Performance Monitor ‘Perfmon’, Sun/Solaris Performance Meter ‘Perfmeter’ and other 3rd party commercial monitoring applications.

How do I detect a memory leak?
· Memory leak problem.
· Memory consumed
· High IIS memory after load test

What metrics/measurements should I collect/review when conducting performance related testing?
· Stress Test measurements
· Response Times versus other metrics
· Measurement for Load/Performance test report
· How can I get the CPU occupation and Memory occupation rate for a period times.
· What to record and how?
· What resources are to be monitored for AppServer
· What resources do you monitor on web server (under load)?
· What my monitors tell me

Scalability and Capacity.
· Vertical Scaling
· Sizing
· Best counters for capacity planning
· Understanding Scalable vs. Capacity
· Difference between Load testing and Capacity Planning

[kiran2710]

Thanx anand....

[abeethabsl]

thx anand

[ranjith595]

i know def. of performance,load,etc but i donot know implemention

so please how to implemention of Performance Test,load test,strees test etc with sample project.