How to Do Leak Testing on an Extension in Mozilla Firefox

Firefox is one of the top three Web browsers in the world.

Web browsers, like Firefox, can develop memory leaks, whereby a page or extension allocates more and more memory unnecessarily. The result of a memory leak is that the overall performance of the computer slows down. Extensions, also called add-ons in Firefox, are small pieces of software that extend the functionality of your browser once downloaded and installed. Add-ons, though useful, can occasionally cause errors. Memory leaks may be caused by an extension, a particular Web page or a combination of the two; regardless of the cause, establishing clear testing parameters will help to isolate the leak.

Instructions

1. Launch Firefox. Open tabs for websites you use often. Press "Ctrl," "Shift" and "Esc" to open the Task Manager. Click the Processes tab and then click Firefox.exe in the list. Note the amount of memory it is using. The memory is listed in kilobytes of RAM; 100,000KB is roughly equivalent to 100 megabytes (MB). If you have a memory leak, the amount of memory being used by Firefox will continue creeping up, even if you close tabs.

2. Disable all the extensions. Press "Ctrl," "Shift" and "A" to launch the Add-ons Manager. Click the puzzle-piece icon on the left to see the extensions you have installed. Click "Disable" next to each extension. Click "Restart Now."

3. Note the memory usage for Firefox without the extensions enabled. Open the same tabs that were open previously. Let the computer sit for 10 minutes and then close the tabs one at at time. See if Firefox's memory usage drops. If it doesn't, or it continues to increase even after tabs are closed, the leak is most likely caused by a webpage that you have open rather than by an extension.

4. Access the Extensions section of the Add-on Manager again and enable one extension. Click the link to restart Firefox and check the memory usage in Windows Task Manager. Repeat the same process of letting Firefox run for 10 minutes and then closing one tab. If you don't see signs of a memory leak with that extension, enable the next extension, restart Firefox and test it again. Repeat for all the extensions you have. Eventually you'll find the one causing escalating memory usage in Firefox.

References

• Mozilla: Troubleshooting Extensions and Themes
• Tech Republic: Reap the Benefits of Windows 7's Task Manager