Optimizing Memory Usage for Add-ons

Editor’s note: This is a short excerpt from Nicholas Nethercote’s personal blog. Nicholas is a programmer from Melbourne, Australia, who works for Mozilla on improving the quality of software. Here’s the good news in a nutshell:

“Over the past year, Mozilla has made great progress in reducing Firefox’s memory consumption. However, the excessive memory consumption caused by add-ons with memory leaks has remained an ongoing problem.

Firefox 15 fixes that problem. We have confirmed, via in-house testing and from real-world telemetry data, that it prevents the vast majority of leaks that occur in existing add-ons.

Users who upgrade to Firefox 15 won’t have to upgrade their add-ons to see the benefits. While it is hard to predict the effect of this improvement on any individual user, many users should experience greatly reduced memory consumption, particularly on long browsing sessions. This should result in better performance, fewer pauses, and fewer crashes.

Mozilla’s MemShrink efforts are ongoing. We have various projects in the pipeline that aim to further reduce Firefox’s memory consumption, and help users understand better how Firefox is using memory. ”

About Nicholas Nethercote

More articles by Nicholas Nethercote…


  1. Justin Lebar

    You can read the full article at https://blog.mozilla.org/nnethercote/2012/07/19/firefox-15-plugs-the-add-on-leaks/.

    July 19th, 2012 at 16:24

  2. Havi Hoffman

    Thanks Justin!

    July 19th, 2012 at 16:30

  3. Bastian

    Hopefully, firebug won’t provoke 100% CPU on Linux, anymore…

    July 20th, 2012 at 00:15

  4. pd

    All hail the Hueyfix once again!

    July 22nd, 2012 at 07:40

  5. Randy

    Unfortunately, Firefox 15 for me is just as bad as Firefox 4 ever was, in terms of memory usage. And it might be worse than Firefox 14. As I write this, it’s consumed over 1.1 GB of memory, which is just crazy.

    Despite all the claimed achievements, clearly Firefox developers are not getting it done. So I want them to stop trying to fix it. What I want is control in my hands. I want to know quickly which tabs are consuming the most memory, and I want to be able to unload them to disk. I want to know quickly which apps are consuming the most memory, and I want to be able to relaunch those apps without having to relaunch Firefox itself.

    September 5th, 2012 at 02:05

    1. Jean-Yves Perrier

      Memory management is not something you can fix by adding a line of code at some place. Like security it is mainly a process that you have to set in place: continuous check, analysis, improvements. There are some in each release, but none fix all the problem, even if some like the one arriving in Fx15 solves a lot of problems.

      About:memory is your friend, it gives info about what use your memory. It is a little cryptic, but you shouldn’t have much problem to figure out which tab or extension is using your memory.

      September 6th, 2012 at 02:09

  6. Attila

    I am very sorry to see that folks who work on firefox code find worse and worse excuses for not doing things the right way; FF used to be the best browser around bar none, and now it’s so bloated I can barely use it; I am still forced to use 3.6.28, and it’s a disgusting data mining strategy to keep telling us that this version is outdated and we should stop using it;
    Either you are not good enough as programmers, or you just don’t care about your users…
    Look mama, no hands !
    Something like that.

    On a more serious note: yes, on the contrary, bugs such as memory leaks ARE sometimes just a line of code poorly written or written incorrecty;
    If I had the power to force the programmers that work on FF to do it the way I wanted it… I would simply make them eliminate all the eyecandy and junk that was PUT IN THE CODE after the version 3.6.28 and start from the scratch

    September 9th, 2012 at 19:26

Comments are closed for this article.