Open Bug 1492781 Opened Last year Updated Last year

Slow browser connections seem to end up in spin loops


(Core :: Graphics: WebRender, defect, P4)





(Reporter: djc, Unassigned)


(Blocks 1 open bug)


(Keywords: nightly-community)

Whenever I'm on a very slow or unresponsive web site, Firefox (recent Nightly on macOS) spins up the CPU hard, causing my laptop's fan to blow and the battery to empty relatively quickly.
Component: General → Networking
Product: Firefox → Core
I do have WebRender enabled, so I was thinking it might even be due to WebRender being inefficient about animating the throbber.
Component: Networking → Graphics: WebRender
Priority: -- → P4
Bug 1461239 fix might make cpu usage more efficient than before.
How much worse is the problem with webrender on vs off?
Flags: needinfo?(dirkjan)
a URL that simulates "slow connections" is
These profiles are after the CPU use has settled down

observation: With WR, CPU goes to 100%, then comes down and settles in 10 seconds or so. Spikes a bit during this times

Non-WR: settles down almost immediately
Actually, it looks like there's not a big difference for me in terms of WebRender vs non-WebRender. Both end up spinning the CPU hard for me.
Flags: needinfo?(dirkjan)
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