1111169 - Session restore of a lot of tabs signifcantly slows down Firefox

Status: RESOLVED DUPLICATE of bug 906076

(Firefox :: Session Restore, defect)

Description

[Andreas Wagner [:TheOne] [use NI]]

I have about 500 tabs (in multiple tab-groups) to be restored at startup. In safe mode, this makes Firefox freeze at startup for around 25secs. Starting the exact same profile with safe mode *and* an empty sessionstore.js takes less than 2secs for Firefox to load.

I'm not sure I can provide my sessionstore.js as it probably contains sensitive information. However, I try to be as helpful as possible.

Comment 1

[Andreas Wagner [:TheOne] [use NI]]

I thought maybe the back/forward information for each tab was slowing down startup, so for each tab I stripped tab.entries to contain only tab.entries[tab.index - 1] but that didn't speed up things.

Comment 2

[David Teller [:Yoric] - still alive but not very active]

Yes, we ran the same kind of experiments. By now, we are almost certain that most of the time is spent in DOM/XUL/XBL creating the tab objects.

Bug 1077652 just optimized the case for runtime, but unfortunately, that won't change anything for startup. We really should reimplement some of xul:browser to make it lazy. Bug 906076 is all about investigating some of this.

Comment 3

[nivtwig]

It seems like a duplicate of bug 1025924