777397 - YSlow possibly causing frequent Firefox hangs

Status: RESOLVED FIXED

(WebExtensions :: General, defect)

Description

[Matt Brubeck (:mbrubeck)]

A user contacted me complaining of frequent 2- to 4-second freezes when running Firefox with ~20 open tabs, with several web development add-ons installed including YSlow 3.1.2 and Firebug 1.10b4.   I asked him to try Gecko Profiler, and he sent back the following profile from a time when Firefox was acting slow:

http://people.mozilla.com/~bgirard/cleopatra/?report=869f03a73dd857485879e7c3b2f196e2f612cc48

About half the time in the profile is spent in YSlow code, with the majority of that in an anonymous function at yslow-ff-pref.js:66.

Comment 1

[Matt Brubeck (:mbrubeck)]

I reported this issue to the YSlow project, with some additional details from inspecting the YSlow 3.1.2 source code: https://github.com/marcelduran/yslow/issues/49

Comment 2

[Marcel Duran]

Thanks for the catch, I just removed the unused getPrefList block and increased startup timeout as an attempt to fix this issue. Please let me know if this really fix the reported issue.

Comment 3

[Marcel Duran]

Just submitted a new Firefox Addon: YSlow 3.1.3 which is pending review: https://addons.mozilla.org/en-US/firefox/addon/yslow/versions/?page=1#version-3.1.3

Comment 4

[Marcel Duran]

And 3.1.3 is now fully reviewed, thanks reviewers!

Comment 5

[Matt Brubeck (:mbrubeck)]

Thanks!  Resolving this as fixed for now, though I can't verify it myself because I was not able to reproduce the problem.  I asked the original reporter to verify the fix, and I'll update this bug if I hear back.