How to enable "average generation time"?

Hi

Reading this help file it says that my piwik should report on “average generation time” per page and also the overall website speed.

http://piwik.org/docs/page-speed/#individual-page-generation-speed

This doesnt appear in my reports at all, im just wondering if its something you need to configure or enable?

Im using piwik 1.9.2

Any help much appreciated

Thanks
Ben

Upgrade to latest Piwik please, where this feature (and dozens others) have been added