When designing a set of performance tests it is necessary to consider pauses between user interactions. This is usually referred to as “think time”, and represents the time between the system presenting the results of an action and the next action being taken. If a load test script doesn’t include any think time at all then the system will be bombarded with requests at a rate that isn’t humanly possible. Depending on the system there are likely to be between 10 and 100 times the interactions generated with zero think time than with realistic scenarios. Continue reading ‘Do your users think?’ »
Posts tagged ‘testing’
When planning to deliver a system based on commercial software it is common to start by using manufacturer’s data on the capability of the product to do initial sizing. (e.g. This will support 200 parallel connected users per CPU.) This data often comes from benchmarking and is valid as long as the test conditions are realistically comparable to your production environment. Continue reading ‘Benchmarking COTS software’ »
When drawing a graph of the response time performance of a system with increasing load it will usually follow a standard profile, namely:
A very low load increasing the load will actually improve the performance of the system slightly. This is because most systems use various caching mechanisms and if there is too little load none of the caches will have data in.- As the load increases a near flat region will be experienced, where all requests act as if they have near dedicated resources available to them. Continue reading ‘The generic system performance profile’ »
