just an addition, because I'm doing something similar: If you are printing the content before measuring the time this can depend on the network connection. So if you are doing this also for statistical reasons and only want to measure how long it took to produce the content you could move the measuring before the print (if possible).
I'm monitoring the request durations of my web application with a munin plugin and recognized the runtime difference between a local call on the server and through the network, if I include the print time.