1671548 - Remove Fission experiment support code and prefs

Status: RESOLVED FIXED

(Core :: DOM: Content Processes, task, P3)

Description

[Chris Peterson [:cpeterson]]

We won't need to run any more Fission experiments after we ship Fission MVP. We can then remove code and prefs added to support our Fission experiments, such as FissionExperimentStatus and the fission.autostart.session, fission.experiment.enrollmentStatus, and fission.experiment.startupEnrollmentStatus prefs.

Can we remove the fission.autostart pref, too?

Comment 1

[Chris Peterson [:cpeterson]]

The fission.experiment.* prefs and code won't be needed after we ship Android Fission.

fission.experiment.enrollmentStatus
fission.experiment.startupEnrollmentStatus

fission.experiment.max-origins.origin-cap
fission.experiment.max-origins.sliding-window-ms
fission.experiment.max-origins.qualified
fission.experiment.max-origins.last-qualified
fission.experiment.max-origins.last-disqualified

https://searchfox.org/mozilla-central/search?q=fission.experiment.&path=&case=true&regexp=false

Comment 2

[Olli Pettay [:smaug][[e-mail]]]

fission.autostart false let's us to disable Fission. And it is false on on Android, so we shouldn't remove that.

Comment 3

[Olli Pettay [:smaug][[e-mail]]]

cpeterson, do you think we'd want to reuse some of the setup for Android, once it gets Fission? Or perhaps we aren't going to use similar type of experiment.

Comment 4

[Chris Peterson [:cpeterson]]

(In reply to Olli Pettay [:smaug][[e-mail]] from comment #3)

cpeterson, do you think we'd want to reuse some of the setup for Android, once it gets Fission? Or perhaps we aren't going to use similar type of experiment.

You can remove all the fission.experiment. prefs. We won't need any of them for our Android Fission experiment.

@ Irene, is the fission.autostart pref needed on Android? IIUC, the Fenix frontend enables or disables Fission when it instantiates GeckoView. So our Android Fission experiment will be controlled by the Fenix frontend code, not any Gecko prefs, right?

Comment 5

[Olli Pettay [:smaug][[e-mail]]]

Desktop firefox needs fission.autostart.

But ok, other prefs could go.

Comment 6

[Artur Iunusov]

I would like to clarify removal of these two settings: fission.experiment.enrollmentStatus, fission.experiment.startupEnrollmentStatus.
They are used by the fission.experiment engine itself.

Do I understand correctly that we should completely drop the current fission.experiments implementation on all platforms?

Comment 7

[Nika Layzell [:nika] (ni? for response)]

(In reply to Artur Iunusov from comment #6)

I would like to clarify removal of these two settings: fission.experiment.enrollmentStatus, fission.experiment.startupEnrollmentStatus.
They are used by the fission.experiment engine itself.

Do I understand correctly that we should completely drop the current fission.experiments implementation on all platforms?

Yeah, we'll drop the full experiment implementation on all platforms, assuming comment 4 is correct about android fission experiments not using them. All of this logic for initializing the preference should be removable, as well as nsIXULRuntime.fissionExperimentStatus, and code which accesses it, though that may be a bit more involved, as I believe this information is included in the telemetry environment and in about:support in various ways.

We'll probably want to keep around the enum variants in the decision enum at least for a bit (https://searchfox.org/mozilla-central/rev/43cb6eca1c3069d46d589d52ab4949257e630d19/xpcom/system/nsIXULRuntime.idl#115-120,144-145), as IIRC these are reflected in telemetry, and we don't really want to change the numbering unnecessarily.

Comment 8

[Artur Iunusov]

Attachment: Bug 1671548 - Remove fission experiment support code and prefs, r=smaug,

Comment 9

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/96e29a67746f
Remove fission experiment support code and prefs, r=smaug,

Comment 10

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/96e29a67746f