Monitoring Web Page Load times (RUM, graphite, statsd, apache)

I am trying to push page load time statistics to statsd and eventually graphite/grafana. I think a reasonable way to do this for this site would be to monitor the page.onLoad() value, but have found limited information about actually doing this with apache. I don't really want to add a bunch of javascript to the pages, and would prefer a method that doesn't actually cause additional load to the page.

I have statsd, collectd, and graphite running. What is a good way to do this?