789877 - UI thread stucks while browsing using proxy with auto configuration script

Status: RESOLVED DUPLICATE of bug 769764

(Core :: Networking, defect)

Description

[Felix Kaiser]

User Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:15.0) Gecko/20100101 Firefox/15.0.1
Build ID: 20120905151427

Steps to reproduce:

My business laptop is connected to a network at office, configurated by DHCP in 10.x.x.x network having a gateway that allows only connections to the company's network. My firefox is configurated to use a proxy configuration script using an URL http://xxx.xxx.local-domain.customer.org:8080/xxx.pac. The script filters some domains and local network subnets where it returns "DIRECT". For all other hosts and addresses it returns "PROXY 10.x.x.x:8080; PROXY 10.x.x.y:8080".


Actual results:

Sometimes when browsing the UI thread of firefox stucks while firefox is loading something from the internet. Especially if there are pages loading a lot of objects or there are two or three or more tabs loading the UI stucks. When the user load on the proxy is low this problem happens less often, on high load more often. This annoyes when loading tabs on background while browsing a complete loaded tab because the UI stucks up to a few seconds and does not respons during this time. First firefox version I've used on this network and proxy was 13.x, the problem still occurs in latest version.


Expected results:

The UI should not stuck, all actions that could block the UI thread should be executed in a background thread.

Comment 1

[Patrick McManus [:mcmanus]]

good news - we've almost got the fix for this completed.

Comment 2

[Felix Kaiser]

What version will include this fix? Got Firefox 16.0 today that doesn't seem to include it.

Comment 3

[Patrick McManus [:mcmanus]]

769764 is fixed in firefox 18. FF 18 is currently on the aurora channel if you'd like to test it.