Faster apps for a faster web: introducing Speed Tracer – Official Google Blog:

Speed Tracer is a Google Chrome extension that enables developers to identify performance problems in their web apps using a “Sluggishness Graph,” in combination with many other metrics. In the spirit of clean, simple design, developers need only look at the Y-Axis of their application’s Sluggishness Graph to see how they’re doing:

* If the y-axis is close to zero, then the app is fast
* If the y-axis registers around 100%, then the app is, well, sluggish
(Link: Faster apps for a faster web: introducing Speed Tracer – Official Google Blog:)