Performance guidelines for decl. WebRequest API

chrome/common/extensions/docs/templates/intros/events.html

Index: chrome/common/extensions/docs/templates/intros/events.html
diff --git a/chrome/common/extensions/docs/templates/intros/events.html b/chrome/common/extensions/docs/templates/intros/events.html
index 8c4156ce19f288c5b8c16d52904c310ec1a57496..19fbabf9be4b12188b8070acfbed9ca86954d4fc 100644
--- a/chrome/common/extensions/docs/templates/intros/events.html
+++ b/chrome/common/extensions/docs/templates/intros/events.html
@@ -164,6 +164,24 @@ function getRules(rule_ids, function callback(details) {...});
 The <code>details</code> parameter passed to the <code>callback()</code> function
 refers to an array of rules including filled optional parameters.
 </p>
+
+<h3 id="performance">Performance</h3>
+
+<p>
+To achieve maximum performance, you should keep the following guidelines in
+mind:

[Mike West, 2013/04/08 13:52:53]

These are excellent tips: I think they'd be even more excellent if you add
example code demonstrating the right way to do things. Developers generally end
up copy/pasting; it'd be good to give them something to start with.

[battre, 2013/04/08 14:42:55]

Done.

+<ul>
+  <li>Register and unregister rules in bulk. After each
+  registration or unregistration, Chrome needs to update internal data
+  structures. This update is an expensive operation.
+  <li>Prefer substring matching over matching using regular expressions in a
+  $ref:events.UrlFilter.  Substring based matching is extremely fast.
+  <li>If you have many rules that all share the same actions, you may merge
+  the rules into one because rules trigger their actions as soon as a single
+  condition is fulfilled. This speeds up the matching and reduces memory
+  consumption for duplicate action sets.
+</ul>
+</p>
 </div>
 {{/is_apps}}