saliences.com : Browser Bugs : Firefox UI Stall

Description

This page attempts to quickly demonstrate a long standing UI bug in Firefox. After continued usage, Firefox’s UI will start periodically stalling for brief periods of time. At first the stalls are imperciptible, but after a while, the stalls become longer and longer which causes the browser to become unusable. A restart of the browser is the only way of recovering.

This test case attempts to simulate a long browsing session by generating large amounts of DOM objects and discarding them continuously (similar to what most AJAX heavy applications do).

This bug is being tracking in Bugzilla under 490122 and 599694

Reproduction Steps

• With a fresh instance of Firefox on Win7, memory usage starts at about 51 MB^*
• Navigate to this page.
• Observe that memory usage starts climbing.
• Every 2000 iterations or so, refresh the page.
• After three or four page refreshes, the UI thread will start stalling.

^* - Reading the “Memory (Private Working Set)” column from the windows task manager.

Iteration Times