608440 - Battery lifetime is decreased with Fennec due to background tabs

Status: RESOLVED WONTFIX

(Firefox for Android Graveyard :: General, defect)

Description

[Austin King [:ozten]]

Sorry if this is anecdotal...

Since I started testing the nightly (and using Fennec every time, instead of occasionally) my battery life has be cut in half or worse.

Hypothesis:
It seems like Fennec stays running longer than the built in browser and for web pages that continue to use CPU when "idle". It's easy to leave these pages in non-visible tabs and forget about them.

I'll try to monitor this with "Spare Parts", but haven't remembered to check since a fresh boot (after running out of juice).

Comment 1

[Alon Zakai (:azakai)]

> Hypothesis:
> It seems like Fennec stays running longer than the built in browser and for web
> pages that continue to use CPU when "idle". It's easy to leave these pages in
> non-visible tabs and forget about them.
> 

I am concerned about this as well. One cause is that we create new tabs silently, without the user noticing (e.g. when loading a normal URL in an about:* page). Perhaps we should do something differently there?

Comment 2

[Austin King [:ozten]]

(In reply to comment #1)
Another tactic would be to put background tabs to sleep after X minutes of not being used. Kind of like the BarTab Add-on's way of lazy loading tabs.

Comment 3

[Alon Zakai (:azakai)]

(In reply to comment #2)
> (In reply to comment #1)
> Another tactic would be to put background tabs to sleep after X minutes of not
> being used.

Something like this has been considered, but it is a change in behavior and might confuse users. For example, if a background tab is playing music, the user might not want it to be put to sleep. There doesn't seem to be an easy way to do this perfectly.

My personal preference would be to do this:

1. Not open new tabs silently.
2. Have an indicator of whether background tabs are open (whenever any of the sidebars or top bar is shown).
3. Somehow warn the user when a significant amount of CPU is being used by content tabs ('Your battery is being drained').
   3.1. If the user has not interacted with the device for a while and we would like to show that warning, perhaps do something more radical (suspend content, until the user requests it be run?)

Comment 4

[BMO Automation]

Closing all opened bug in a graveyard component