Measure App Response Time with Apache

One of the most common challenges of running any website is getting good metrics on how well your app is doing at spitting out the initial payload. Apache's builtin log value (%D) measures the time from connection open to connection close, which takes into account lots of inconsistent variables like connection speed and browsing habits.

However, there's an Apache module (modlogfirstbyte) that will measure the time between the request being read, and when the first byte is sent to the client. For most apps, this is the time that's spent on the server actually processing the request.

See here for code examples.