Profiling of web requests in Parallels Business Automation - Standard is very useful. This allows understanding, which requests are slow (from some IP address, or to some specific URL, etc.).
You can measure time needed to access the requested web page with the help of HSPC profiling. This allows you to check the performance and spot slow pages needing improvements.
You are not recommended to use profiler all the time as it is likely to put an additional load on your system resources and disk space. When profiling is turned on, performance will reduce, mostly due to operations with file system (for saving log files).