Not sure I understand the question. We use an external library for adding metrics to various parts of the platform. But you have to define explicitly what you measure, by inserting the corresponding metrics hooks.
In S4 we tried to factor metrics management in an S4Metrics class, but that is mostly for clarity.
See the library documentation here http://metrics.codahale.com/ for more info on how to use the same library, though there are others.
Hope this helps,
On May 28, 2013, at 12:19 , Sky Zhao wrote:If using Metrics in project, not affect source code, I am ready to use inject event into s4, how to do it,Can you give some examples,but the Metrics links is still not clear.Thanks first/Sky