I'm new with website performance testing field and will be using JMeter. After playing with it, I am still having troubles with identifying what to optimize in a website load time?
I'm currently still learning about the load testing - who should I give the performance report to? Developers/Programmers? or Network department? Example of an error I usually get is 502 error or timeouts.
Thanks in advance.
JMeter cannot identify anything, all it does is executing HTTP requests and measuring response times. Ideally it should be you, who takes JMeter raw results, performs analysis and creating the final report highlighting current problems and bottlenecks (and ideally what needs to be done to fix them)
Consider the following checklist:
- You load test needs to be realistic, a test which doesn't represent real-life application usage does not make sense. So make sure your JMeter test carefully represents real users in terms of cookies, headers, cache, downloading images, styles and scripts, virtual user groups distribution, etc.
- Increase and decrease the load gradually, this way you will be able to correlate such metrics as transactions per second and response time with increasing/decreasing number of users so make sure you apply reasonable ramp-up and ramp-down settings.
- Monitor the application under test health. The reason of error may be as simple as lack of hardware resources (CPU, RAM, Disk, etc.). It can be done using i.e. PerfMon JMeter Plugin.
- Do the same for JMeter instance(s). JMeter measures response time from "just before sending the request" until "last response byte arrives" so if JMeter is not able to send requests fast enough - you will have high response time without other visible reason.