Multi-Process Plugins Enabled In Latest Firefox Nightlies

Martin Brinkmann
Feb 1, 2010
Updated • Jul 21, 2016

Mozilla enabled multi-process plugin support in Firefox recently which has plugins run in their own process separated from the browser

Only Microsoft's Internet Explorer and the Google Chrome web browser are full multi-process web browsers at the time of writing.

Multi-process refers to the use of multiple processes on the operating system for browser functionality. In the case of Firefox, that is one process for the browser core and another for plugins. Google Chrome uses multi-processes for individual websites and other contents as well taking it yet a step further than Firefox.

While a multi-process architecture impacts RAM use, it is beneficial for stability. If a plugin crashes, it won't take the whole browser with it for instance as only its own process is terminated eventually.

Multi-Process Plugins Firefox

Mozilla announced last year that it made the decision to introduce multi-process support in the Firefox browser.

The first step towards the goal has now been introduced in the latest Firefox Nightly version, the cutting edge development version of Firefox.

Firefox will separate plugin content, Adobe Flash for example,  from the main browser process to improve stability and security. Firefox users who check the task manager or another process manager will notice a Firefox process, and additional processes for plugins that are running.

This new feature is currently available only for Firefox for Linux or Microsoft Windows. It comes with a few issues that the developers are aware of including:

The plugin-crash UI is not finished. The current UI is just a non-localized dialog so that we can get crash reports from nightly testers. This will be changed soon!
On Windows, tearing/repainting issues when scrolling, bug 535295
On Linux, compiz effects and Flash don’t work together on some systems, bug 535612
On Windows, selecting “Print” option in Flash may lock up Firefox, bug 538918
On Windows, hulu won’t switch to full-screen mode, bug 539658
On Linux with GTK+-2.18 or later, GDK assertions and a fatal XError, bug 540197
Firefox-process crashes at NPObjWrapper_NewResolve with silverlight and sometimes Flash, bug 542263

Firefox users who want to test the new multi-process architecture are asked to submit any bugs that they find to Bugzilla so that the developers can analyze and remove them from the web browser.

The new feature can be disabled by setting the Firefox preference dom.ipc.plugins.enabled to false. (via Benjamin Smedbergs)

Update: Things have changed a bit since 2010. The mozilla runtime process that you see on the screenshot is not used anymore. You will see Flash plugins displayed directly instead.

flash process

As you can see, multiple FlashPlayerPlugin processes are launched when you run Flash content in Firefox.

Multi-Process Plugins Enabled In Latest Firefox Nightlies
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Multi-Process Plugins Enabled In Latest Firefox Nightlies
Mozilla enabled multi-process plugin support in Firefox recently which has plugins run in their own process separated from the browser
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  1. Simon Moon said on February 3, 2010 at 8:47 am

    Funny thing is, Mozilla produces nightlies for all branches. Maybe you should say that this new functionality is available in the trunk-nightlies or mention the 3.7a1 branch.

  2. BalaC said on February 2, 2010 at 4:01 pm

    Martin, i think there is a typo

    These developer releases will not separate plugins into different processes

    Do you mean

    These developer releases will separate plugins into different processes

    1. Martin said on February 2, 2010 at 5:48 pm

      You are right, I meant to say Now not not. Corrected.

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