1233464 - Firefox hangs when I open additional tabs when there are ~100 open and 1500 inactive tabs already

Status: UNCONFIRMED

(Firefox :: Tabbed Browser, defect)

Description

[gavenkoa]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:29.0) Gecko/20100101 Firefox/29.0
Build ID: 20151104000845

Steps to reproduce:

Just open 4 new tabs via Ctrl+Click on links from Google search.

I have near 1500 tabs and 100 of them are active.

about:memory shown 5 GiB memory allocated.

I run Firefox for a long time (several days with "sudo pm-suspend") and browser rich pages (coursera.org, etc).

Following report measured during Firefox hangs:

https://cleopatra.io/#report=c869295afa8d5f001ca2642e8dbf85a695b62ba4

Following report measured some time later, when Firefox become responsive again:

https://cleopatra.io/#report=6b7fb1a0c492f616f3eb08dceb14c3f82e88fc8f

Both report show that near 29% / 32% time spent in Timer::Fire => (JS:RunScript + JS::UnmarkGrayGCThingRecursively) and profiler shown site icons / URLs.

I assume that activity just regular JS activity on browser tabs.

I see difference in another leaf - "NM_observeActivity" call, here it is:

https://dxr.mozilla.org/mozilla-central/source/devtools/shared/webconsole/network-monitor.js#664

When Firefox hangs it spent 46% of time in that function while second report spent near 
29% in __poll call of glibc.so.



Actual results:

Firefox hangs for several minutes with long or no response.

Comment 1

[gavenkoa]

Sorry, I fake **user agent** as some sites don't work with Iceweasel string.

It is no longer in Debian experimental (at 42.0-1 for AMD64), but here is old signed announce for build:

https://packages.qa.debian.org/i/iceweasel/news/20151104T070026Z.html