Electrolysis/Multiple content processes

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After e10s is enabled for all users, the next step was to introduce multiple content processes. The goal is to bring out the most from the multi process architecture we introduced with e10s, gain performance where it's possible and minimize the impact of content process crashes. The challenge is to achieve this without sacrificing the advantage we currently have in memory usage compared to our competitors.

The first step was to enable 4 content processes to all users without non WebExtensions based add-ons. Before increasing the number of maximum processes the next step is further optimization. Memory consumption and content process startup time optimization, memory balancing among content processes and user machine based customization based on performance statistics.

One explicit non-goal of this project is to nest content processes for e.g. iframes. There is work underway to do that in bug 1277066 in parallel to this project.


Version Status
56 Maximum 4 content processes for all e10s eligible users without any non WebExtension add-ons
57 Maximum 4 content processes for all e10s eligible users
58 No longer relying on the system add-on, prelaunching content process in the background

Memory management

Content process startup time

  • ~300ms - on most platforms (the OSX issue is investigated under: bug 1404309)
  • The preallocated process manager is enabled from 58

Current work

Talos test to measure parallel page loads bug 1409002
Telemetry probe to measure background process activity bug 1388280
Process selection based on memory footprint bug 1388277
Restarting troubled processes bug 1374353
Selecting max content process count based on users machine ...

Future plans

Compressing strings in JSMs ...
Reduce resources loaded in the CP ...
Reduce static tables ...
Reduce or improve per process caches ...
Long term
Suspending / Freezing background tabs and processes ...
Battery life saving mode ...
Sharing scripts ...

Bug tracking