E10s Update: May 5

Executive Summary

As of Firefox Release 53 (Early May) 54.77% of the total release population have e10s (as compared to 52.82 in Firefox 42 in early April). Single process e10s is active for non add-on users, and add-on that are web extensions or SDK add-ons actively marked compatible by the author.

e10s-multi was enabled as of Firefox 54 Nightly with 4 content processes. As of Firefox 54 Beta 1, we launched our first multi A/B test with an experiment split of 10% Control and 90% test. As of Beta 3, the Test population is split evenly across two cohorts: single process and multi-process. The metrics we are monitoring since we released the first experiment include:
Our forecast for the engineering schedule tracks to being MVP as of 55 and we are working to uplift as much as possible to 54 with an eye towards shipping in 54 so long as we meet or exceed our release criteria (we are aiming for release 54 for initial roll-out, for at least some part of the population).

The team is currently focused on correctness, measuring performance and memory, and Scaling to 4 Processes. You can read more about what this means in the e10s-multi wiki. Basically, we are working hard so multi can ride the trains for 54/55.
The E10s-Multi plan is taking shape: our current forecast predicts that engineering MVP will be complete before the end of Firefox 55. We are currently 80% complete.
- Our last hard Service Workers dependency bug 1346247 was just uplifted to Aurora 55 as of this morning. \o/
- Beta experiment design has been determined and we are making progress with the system add-on changes and subsequent validation bug 1349363, bug 1352388.
- Creating a detailed week-by-week release plan is a work in progress.
- Final approval on release criteria and making sure any new telemetry requirements are filed.
- Creating a test plan is assigned and currently in progress.

E10s support for RTL versions of Firefox on Linux is still planned for Firefox 52 (Windows and Mac shipped in Firefox 50).
A11y and touchscreen support has landed in 51. Support Windows 8 and Windows 10 shipped in 52.
The plan is to ship A11y for Windows for Firefox 55.