Level 32
Mozilla is working on integrating a process manager into the organization's Firefox web browser. A preview of the upcoming process manager is now available in recent Firefox Nightly development builds; reason enough to take a look at it to see what it is all about.

Mozilla added a Task Manager of sorts to Firefox in 2018 when it launched the new tool in the browser. First available in Nightly builds only, the Task Manager was launched eventually in Firefox Stable. All Firefox users may open about:performance in the address bar to get energy readings and memory impact information on every open tab, extensions, and browser internals.

Unlike the Task Manager, which focuses on memory use and energy use of open tabs and extensions for the most part, Firefox's upcoming Process Manager provides information that may be useful mostly to engineers and users interested in technical details.

Load about:processes in the address bar to get started. The current iteration of the Process Manager divides the data into browser, socket, gpu, web, extension and privilegedabout (with one web reading for each open site in the browser).

Firefox displays the resident and virtual memory, user and kernel CPU usage, and thread for each entry. You can expand individual data points, e.g. a Web or browser section, to get sub-listings. If you open a web process, you get readings for JavaScript, PaintThread, or Decoding activities; these are limited to CPU usage at the time of writing though.

The detailed view level is mostly useful to developers and engineers. Extension developers may be able to get some information from the new Process Manager in Firefox as well provided.

Most regular users of Firefox will have little use for the process manager if it remains in its current form. While it may be useful to find out about individual memory usage and CPU usage, it is difficult to link certain information, e.g. web process information, to an actual site (unless only one is open).

Interested users can check out the meta bug on Bugzilla. The feature may land in Firefox 78 at the earliest. The version of the browser is scheduled to arrive on June 30, 2020.