Bottlenecks can occur during performance testing and load testing or performance modelling exercises. They can also of course turn up unannounced in your production environment.
When something breaks, or response times suddenly elongate in your production environment, it is natural to try and work out what has changed.
What has been introduced to the application so that performance is suffering and your users are complaining? Maybe there has been a code drop? Maybe a configuration has been amended? This can be a good approach and backing out the change could resolve the performance issues. This is not always the case.
Our company has the expertise at hand to investigate and diagnose performance problems quickly and efficiently.