e10s Update: May 9

Executive Summary

e10s-multi was enabled as of Firefox 54 Beta 1 with 4 content processes. Currently 21.15% of the 54 Beta population has e10s-Multi enabled. The project is designated as 'At Risk' until we have met our release criteria. See below for more information.

As of Firefox Release 53 (Early May) 53.76% of the total release population have Single-Process 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.

[ON TRACK] Stability. We have a tight correlation between single process and multi-process crashes which is good. We are concerned that the WebExtensions crashes in the content crash rate is higher than Non Web-Extensions and are figuring that out.
[AT RISK] % of population shows us we'd like to increase the number of people we roll e10s-mutli out to.
[AT RISK]Performance numbers on Talos shows us a regression in responsiveness for TP05 which is being addressed.
[IN PROGRESS] Pending items related to release criteria data includes analysis on memory usage and Performance Telemetry numbers are forthcoming within the next couple of business days.

The % of Beta Users with e10s-Multi activated in shows us that our initial experiment design doesn't activate E10s-Multi for as many users as we would like. 10% of the population is in the control group and 90% is in test, however, only 46% have e10s active and 21% which is has Multi enabled. We are currently activating e10s-Multi for users who either do not have add-ons installed or who are using WebExtensions only. Product's sentiment is that this approach is too conservative and is evaluating risk vs. reward for expanding the experiment to include MPC=True Add-Ons for e10s Multi. This decision will be made by May 12th.

A go/no-go decision for doing an initial roll-out for Multi in Firefox 54 will happen no later than June 3rd.

Engineering highlights include recently landed bug 1341008 Use the preallocated process manager by default which Preloads a content process in the background when the browser is idle and using that the next time we need one which will greatly improve load time.
Top issues we are investigating include:
bug 1336398 [e10s-multi] Talos tps page load times have grown increasingly erratic for 32-bit Win7 e10s compared to non-e10s
bug 1363240 Content process limit specified by dom.ipc.processCount is not respected in some circumstances

[AT RISK] The plan is to ship A11y for Windows for Firefox 55; this project is designated at risk until all MVP requirements are complete.