Speed Tracer Hints

Speed Tracer analyzes your application and reports hints when it finds a potential performance problems that can degrade the user experience. Each hint is generated by a JavaScript rule definition and is flagged with one of three priority values, which depend on the severity of the issue.


Built in Rules

Long Duration Event

A top level event blocked the browser UI for an excessive amount of time.
(INFO) Event took 100 milliseconds or longer.
(WARNING) Event took 2 seconds or longer.

Excessive Layout

Frequent layout is adding up to a non-trivial amount of time.
(WARNING) At least 3 layout sub-events totaling 70 milliseconds or greater.

Total Bytes Downloaded

A large amount of data was downloaded to load the current page. The thresholds are reset after a page transition.
(INFO) Cumulative download size is 500kB or greater.
(WARNING) Cumulative download size is 1MB or greater.
(CRITICAL) Cumulative download size is 2MB or greater.

Google Web Toolkit (GWT) Detection

Warns of inappropriate cache settings for a GWT selection script. The selection script should be served with no-caching enabled so that, when the application is upgraded, stale pages are not served from client side cache.
(CRITICAL) GWT selection script served with no-caching disabled.

Rules from Page Speed

The following rules are derived from the Page Speed tool. Please consult the Page Speed documentation for more information about these recommendations.

Caching rules

These hints have to do with optimizing client side caching.

Compressed Content

Advises you to compress content to save download time.


Advises you to serve static data from cookieless domains.
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