Fission Newsletter #9

[Neha Kochar]

Greetings Everyone,

A lot has been accomplished since our last newsletter so we are back with
more Fission news in our Newsletter #9.

Experimenting with Fission in Nightly

With the completion of Fission milestone M6b, Fission Nightly experiment
was launched for 5% of Nightly on October 13. We observed surprisingly good
results in the first three weeks and decided to increase the experiment
percentage to 10% of Nightly on November 3. We continue to monitor the
results and the experiment data
<https://protosaur.dev/fission-experiment-monitoring-dashboard/dashboard/dashboard.html>
is looking very good. One of the notable impressive ones is lower
checkerboarding severity with Fission enabled (read here
<https://searchfox.org/mozilla-central/source/gfx/docs/AsyncPanZoom.rst#93-110>
if you’re interested in finding out what does checkerboarding represent).


Other performance and memory probes are also showing Fission results within
the noise level when compared to the non-Fission measurements, which is
great!. Below are some examples of this.




Arriving at the Finish Line

We are very glad to report the completion of Frontend migration of all
framescripts to JSActors. Also, equally happy to report that printing of
out-of-process iframes is now working and complete. If you still see any
issues, please report them for the `Core::Printing:Output` component
blocking the meta printing-fission
<https://bugzilla.mozilla.org/show_bug.cgi?id=1480547> bug.

Fission Performance

Visual metrics performance dashboards have been added for Fission at
https://arewefastyet.com
<https://arewefastyet.com/linux64/cold-page-load/overview?numDays=7> for
Linux64. Some of the sites are showing performance regressions for Fission
and we are looking into debugging and adding optimizations to improve those.

Session Storage Moved to the Parent Process

One of the major themes with Fission has been the move from content
processes to parent process. Continuing with that theme, Session Storage
has also been moved to the parent process in Bug 1654080
<https://bugzilla.mozilla.org/show_bug.cgi?id=1654080>.

See your processes

Fission added a new about:processes page to show users more information
about the different processes Firefox uses and the corresponding origins
loaded in them. It groups the same sites from different tabs and frames
together for better readability and shows corresponding CPU and memory
usage. Double-clicking on any row representing a tab in about:processes
will take you to that tab. Also, the last column in about:processes allows
the user to kill a tab or a process by clicking on the ‘x’. Bug 1674084
<https://bugzilla.mozilla.org/show_bug.cgi?id=1674084> enabled
about:processes to ride the trains starting with Firefox 84.


Help Firefox get Fission-ready

You can help us test Fission on Firefox Nightly by enabling Fission in
about:preferences#experimental followed by restarting Firefox for it to
take effect.


For any follow-ups or comments or questions, you can find us at #fission in
Slack and Matrix/Element.

-The Fission Team.