482642 - High CPU use when waiting for slow HTTP proxy (TOR) to connect

Status: RESOLVED INCOMPLETE

(Firefox :: General, defect)

Description

[hxxp]

User-Agent:       Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9) Gecko/2008052906 Firefox/3.0
Build Identifier: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.9) Gecko/2008052906 Firefox/3.0

When using a HTTP proxy, firefox uses 50-99% CPU when waiting for the proxy to connect to a site.
If i minimize firefox, the cpu activity drops to 1%, and it will continue loading the site properly.

Reproducible: Always

Steps to Reproduce:
1. Install and run tor vidalia bundle
2. Configure firefox to use http proxy 127.0.0.1 port 8118
3. Visit any website
Actual Results:  
99% CPU use by firefox.exe until the connection is completed

Expected Results:  
1% or normal CPU use, same as if it was minimized

I notice this mostly because i am using TOR (torproject.org) which can be quite slow to respond, maybe the dev's didn't notice it because if the proxy is fast to respond, there is no problem.

I am using firefox 3.0.7 even tho the help/about says 3.0.

Comment 1

[Ria Klaassen (not reading all bugmail)]

Please retest with a new profile: http://support.mozilla.com/en-US/kb/Basic+Troubleshooting#Make_a_new_profile
If the problem, including the UA string problem, is still present try reinstalling Firefox in an empty folder (first delete the contents of the installation folder manually).

Comment 3

[Matthias Versen [:Matti]]

Ria: Do you duped to the right bug ?
bug 138372 is from 2002 and only marked wfm because the reporter didn't answer

Comment 4

[Ria Klaassen (not reading all bugmail)]

Reporter, if comment 1 doesn't help to resolve your problem and/or you think the bugs are not basically the same, you can always choose to reopen this bug. 
BTW, see also http://support.mozilla.com/en-US/kb/Firefox+hangs

Comment 5

[hxxp]

New profile does not help.
Same problem.
I removed it completely and reinstalled, deleted folder from my windows profile too.
The only thing changed was the proxy.

The reason for the user-agent is I have a custom set (fake) useragent using general.useragent.override but thats unrelated to the bug.

I have seen this problem for a long time, and have seen it on 3 different pc's (xp/vista/windows 7), some which have windows reinstalled a few times since.

It definitely happens all the time.

Some additional info:
When uploading a file with http proxy, the high cpu use occurs during the entire length of the upload.
Same problem when waiting for an image on the page to load.

The CPU use seems to occur the entire time between when the socket is opened, until the first line of the http response is received.

Comment 6

[Tyler Downer [He/Him]]

This is a mass search for Firefox General bugs filed against version 3.0 that are UNCO and have not been changed for 200 days.

Reporter, please update to Firefox 3.6.10 or alter. Firefox 3.0 is no longer supported and is no longer receiving updates. After you update, please create a fresh profile, http://support.mozilla.com/kb/managing+profiles, and test to see if your bug still exists. If you still the bug, then please post a comment with the version you tested against, and the problem. If the issue is no longer there, please set the RESOLUTION to  RESOLVED, WORKSFORME.

Comment 7

[Tyler Downer [He/Him]]

No reply from reporter, INCOMPLETE. Please retest with Firefox 3.6.12 or later and a new profile (http://support.mozilla.com/kb/Managing+profiles). If you continue to see this issue with the newest firefox and a new profile, then please comment on this bug.

Comment 8

[Francois Guerraz]

Hi,

I suspect the problem is still here and is unrelated to proxy connections.

I'm using FF 13.0.1 on Mac OSX Lion on a very slow connection (I'm on a satellite link) and just waiting on an unresponsive website (on a SYN_SENT, no established connection) uses 15%CPU (on a i7!), minimizing the window helps (CPU drops down to <5%).

Downloading a file at 3kb/s for example uses 15%CPU too, basically doing nothing !
I suspect the usage comes from the UI refreshing the download progress bar or just the spinning wheel in the tab which is *ridiculous* because it wakes up the CPU very often and halves my battery life!

I don't have this problem with Safari, so I'm abandoning FF little by little...

Would be nice to fix or have a configuration option for those who prefer battery life over abusive UI refreshing! :)

François

Comment 9

[Francois Guerraz]

Hi!

Relative to my latest comment, do you think I should open a new bug for that or is this one going to be reopen ?

Cheers,

François.

Comment 10

[David von Oheimb]

I can confirm that this old bug is still present in Firefox 27.
When using Firefox only a slow or flaky connection (e.g., an overloaded WiFi router) or uses an HTTP proxy that is not properly configured or not responding properly, loading pages results in high CPU load until the connection times out, or sometimes even indefinitely. 
Obviously there is some busy loop waiting for the connection.

Please re-open!

Comment 11

[David von Oheimb]

As I wrote for the related bug 919485, it is straightforward (for anyone on any version!) to reproduce it:
Simply put any garbage IP address and port number in the HTTP proxy settings and re-load any page.

This phenomenon is still present in TB 31.2.0, and in FF 33.1.
I wonder why this 5+ years old bug is still marked as RESOLVED INCOMPLETE..

Moreover, those ugly battery-wasting bugs due to busy loop(s) on connect should hot be too hard to correct. My guess is that all of them can be traced down to a single careless chunk of low-level code.