948528 - [meta] Spikes in power usage during idle

Status: RESOLVED WORKSFORME

(Firefox :: General, defect)

Description

[Roberto Agostino Vitillo (:rvitillo)]

This bug tracks the work related to the energy drain of Firefox when idle.

Comment 1

[Roberto Agostino Vitillo (:rvitillo)]

The energy drain of FF 25.0.1 during idle on Windows, Linux and OSX are very similar in my tests:
- the donate gif in about:home is draining up to 33% more energy wrt. the idle machine
- without the donate gif FF does not seem to drain any additional energy

Comment 3

[Roberto Agostino Vitillo (:rvitillo)]

Even though Intel Power Gadget doesn't seem to show any statistically significant drain during idle on my machine, there are some wakeups triggered due to mainly:

- bug 951713
- bug 951671
- Watchdog
- nsIdleService
- gfxFontCache::WordCacheExpirationTimerCallback (disabled in release)

were the last three are required but have a low frequency. I suspect that the power drain is difficult to spot when profiling "short" intervals (1-10min) whereas the effect could be visible over much longer intervals.

Comment 4

[Roberto Agostino Vitillo (:rvitillo)]

Correction: the wakeups triggered during idle by gfxFontCache and Watchdog could be avoided.

Comment 5

[Roberto Agostino Vitillo (:rvitillo)]

The wakeups triggered by Watchdog are caused by Bug 958552.

Comment 6

[Nicholas Nethercote [inactive]]

This meta-bug now has only one blocker, and it hasn't seen any significant activity since early 2014. I think it's served its purpose and can be closed.