Electrolysis/Multiple content processes: Difference between revisions

From MozillaWiki
Jump to navigation Jump to search
(removing section, no longer needed)
(current work + future plans)
 
(21 intermediate revisions by 3 users not shown)
Line 1: Line 1:
== Goals ==
After e10s is enabled for all users, the next step is 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.


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.
= Overview =
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.


== What to expect ==
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.  
First, we will enable 2 content processes and fix correctness bugs in the DOM and frontend components. Then we will start ramping up the number of content processes while optimizing memory use in order to avoid using too much memory overall. Once we have that we can think about advanced process models, sandboxing and how can we get the most out of multiple content processes.


== Roadmap ==
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.
=== M1[Nightly {{bug|1303113}}]: enable 2 content processes on nightly (Done) ===
Apart a few corner cases 2 content processes are fairly stable for everyday usage. Our hope is that by enabling 2 content processes on nightly despite a few known issues that will be time consuming to fix (session storage / shared workers) we will get better bug reports early.
* Ignore memory footprint.
* Fix crash report in background tabs {{bug|1241459}}
* '''Known issues that will block riding the train but will not block enabling 2 content processes on nightly:'''
** Service/Shared workers should run in their own process: {{bug|1231208}}
** Some test will need some refactoring: {{bug|1301015}} but for now we will force them to use single content process: {{bug|1301340}}


=== M2[Aurora {{bug|1304546}}]: Correctness, Measuring Performance and Memory, and Scaling to 4 Processes===
= Status =
* Measure the memory footprint of content processes
{| class="wikitable"
* Measure startup of content process ({{bug|1336389}}, {{bug|1304790}})
|-
* Start optimizing memory use
! Version !! Status
* Prepare to go beyond 2 content processes (aiming for 4 initially {{bug|1336398}}).
|-
* Service Workers in it's own content process
| 56 || Maximum 4 content processes for all e10s eligible users without any non WebExtension add-ons
* AWSY ({{bug|1272113}})
|-
 
| 57 || Maximum 4 content processes for all e10s eligible users
=== M3[Beta {{bug|1304547}}]: Optimization and Preparing for Release ===
|-
* Memory optimization
| 58 || No longer relying on the system add-on, prelaunching content process in the background
* Performance optimization
|}
* Solidifying Automated tests (working with module owners)
== Memory management ==
* General Convergence; focusing on quality
 
== Meetings ==
We are meeting every week at 9am PDT (6pm CEST) starting on June 28.
 
== Core Development Areas ==
 
=== Memory management ===
* [http://www.erahm.org/2016/02/11/memory-usage-of-firefox-with-e10s-enabled/ Memory cost of a content process] - relatively high
* [http://www.erahm.org/2016/02/11/memory-usage-of-firefox-with-e10s-enabled/ Memory cost of a content process] - relatively high
* [http://www.erahm.org/2016/02/12/are-they-slim-yet/ Memory usage of e10s compared to other browsers] - we're not the worst offender
* [http://www.erahm.org/2016/02/12/are-they-slim-yet/ Memory usage of e10s compared to other browsers] - we're not the worst offender
* Extending Nuwa for all platform does not seem realistic, and since the most memory overhead comes from JS, we should address the problem at JS engine level first. Till Schneidereit suggested [https://bugzilla.mozilla.org/show_bug.cgi?id=876173 lazy cross-process memory sharing].
* [https://bugzilla.mozilla.org/show_bug.cgi?id=1381961 Enabled shared global for JSMs]
== Content process startup time ==
* [https://treeherder.mozilla.org/perf.html#/graphs?series=mozilla-central,1559690,1,1&series=mozilla-central,1559693,1,1&series=mozilla-central,1559696,1,1&series=mozilla-central,1559697,1,1&highlightedRevisions=8a3b8491838e ~300ms] - on most platforms (the OSX issue is investigated under: [https://bugzilla.mozilla.org/show_bug.cgi?id=1404309 bug 1404309])
* The preallocated process manager is enabled from 58


== Add-ons ==
= Current work =
* Web extension testing seems to be broken with the multiple content processes
{| class="wikitable"
* SDK based add-ons probably come with a big memory overhead per process.
|-
* Out of process WE add-ons is not part of the project
! Metrics !!
* Some add-ons might break because of false assumptions (JSM has to be loaded per process now for example)
|-
 
| Talos test to measure parallel page loads || {{Bug|1409002}}
== Testing ==
|-
* [https://bugzilla.mozilla.org/show_bug.cgi?id=1251962 Existing tests should work with 2 content processes.]
| Telemetry probe to measure background process activity || {{Bug|1388280}}
* [https://bugzilla.mozilla.org/show_bug.cgi?id=1251963 Areas where additional testing is needed have to be identified.]
|-
 
! Tuning !!
== Performance Testing ==
|-
Current Talos tests gives very little information about the difference between one and multiple content processes. We need more tests.
| Process selection based on memory footprint || {{Bug|1388277}}
|-
| Restarting troubled processes || {{Bug|1374353}}
|-
| Selecting max content process count based on users machine || ...
|}


= Future plans =
{| class="wikitable"
{| class="wikitable"
! Memshrink !!
|-
|-
! Some tests should use
| Compressing strings in JSMs || ...
multiple tabs simultaneously
! Others are irrelevant
! Additional test we need
|-
|-
| sessionrestore<br>
| Reduce resources loaded in the CP || ...
sessionrestore_no_auto_restore<br>
tps<br>
tresize<br>
tart<br>
| ts_pain<br>
tsvgx<br>
tsvg-opacity<br>
dromeo<br>
a11y<br>
tscrollx<br>
tresize
| Running active web content
simultaneously in multiple tabs
|-
|-
| 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 ==
= Bug tracking =
* [https://bugzilla.mozilla.org/buglist.cgi?list_id=13206351&resolution=---&resolution=FIXED&resolution=INVALID&resolution=WONTFIX&resolution=DUPLICATE&resolution=WORKSFORME&status_whiteboard_type=allwordssubstr&query_format=advanced&status_whiteboard=%5Be10s-multi%3AM1%5D&bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED '''M1'''] [e10s-multi:M1] in whiteboard
* [https://bugzilla.mozilla.org/buglist.cgi?list_id=13072930&resolution=---&resolution=FIXED&resolution=INVALID&resolution=WONTFIX&resolution=DUPLICATE&resolution=WORKSFORME&status_whiteboard_type=allwordssubstr&query_format=advanced&status_whiteboard=%5Be10s-multi%3AM2%5D '''M2'''] [e10s-multi:M2] in whiteboard
* [https://bugzilla.mozilla.org/buglist.cgi?list_id=13115346&resolution=---&status_whiteboard_type=anywordssubstr&query_format=advanced&status_whiteboard=%5Be10s-multi%3AM%3F%5D%20%5Be10s-multi%3A%3F%5D&bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED&bug_status=VERIFIED '''Triage'''][e10s-multi:?] in whiteboard
* [https://bugzilla.mozilla.org/show_bug.cgi?id=1231208 '''ServiceWorkers meta'''] owners: Ben Kelly, Andrew Sutherland
* [https://bugzilla.mozilla.org/show_bug.cgi?id=742822 '''LocalStorage refactoring'''] owner: Jan Varga


== Links ==
== Triage ==
* [https://bugzilla.mozilla.org/buglist.cgi?list_id=13712205&resolution=---&status_whiteboard_type=anywordssubstr&query_format=advanced&status_whiteboard=e10s-multi%3AM%3F%2C%20e10s-multi%3A%3F Triage list] ('e10s-multi:?' in whiteboard)
 
== Priorities ==
* [https://bugzilla.mozilla.org/buglist.cgi?priority=P1&list_id=13845618&resolution=---&resolution=FIXED&resolution=INVALID&resolution=WONTFIX&resolution=DUPLICATE&resolution=WORKSFORME&status_whiteboard_type=allwordssubstr&query_format=advanced&status_whiteboard=e10s-multi%3A%2B&bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED P1]
* [https://bugzilla.mozilla.org/buglist.cgi?list_id=13845621&status_whiteboard_type=allwordssubstr&status_whiteboard=e10s-multi%3A%2B&priority=P2&resolution=---&resolution=FIXED&resolution=INVALID&resolution=WONTFIX&resolution=DUPLICATE&resolution=WORKSFORME&query_format=advanced&bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED P2]
* [https://bugzilla.mozilla.org/buglist.cgi?priority=P3&list_id=13845618&resolution=---&resolution=FIXED&resolution=INVALID&resolution=WONTFIX&resolution=DUPLICATE&resolution=WORKSFORME&status_whiteboard_type=allwordssubstr&query_format=advanced&status_whiteboard=e10s-multi%3A%2B&bug_status=UNCONFIRMED&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED P3]
 
= Links =
* [https://docs.google.com/a/mozilla.com/document/d/14E5ERudaZrx-qcOLttXGkV6DgHIyp3h9IZoqnhuO7X8/edit Process Model] (2012)
* [https://docs.google.com/a/mozilla.com/document/d/14E5ERudaZrx-qcOLttXGkV6DgHIyp3h9IZoqnhuO7X8/edit Process Model] (2012)
* Recent [https://groups.google.com/forum/#!searchin/mozilla.dev.platform/e10s$20multiple$20processes/mozilla.dev.platform/NHIjpGvOelE/_A9IJWsP0fUJ dev.platform] discussion
* Recent [https://groups.google.com/forum/#!searchin/mozilla.dev.platform/e10s$20multiple$20processes/mozilla.dev.platform/NHIjpGvOelE/_A9IJWsP0fUJ dev.platform] discussion
= Teams =
TBD

Latest revision as of 12:46, 6 November 2017

Overview

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.

Status

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

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

Future plans

Memshrink
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

Triage

Priorities

Links

Teams

TBD

Retrieved from "https://wiki.mozilla.org/index.php?title=Electrolysis/Multiple_content_processes&oldid=1183518"