597984 - all tabs and ui freeze while processing http request in any one tab on high ping connection

Status: RESOLVED DUPLICATE of bug 769764

(Firefox :: General, defect)

Description

[Jitin Sameer]

User-Agent:       Mozilla/5.0 (Windows NT 5.1; rv:2.0b6) Gecko/20100101 Firefox/4.0b6
Build Identifier: Mozilla/5.0 (Windows NT 5.1; rv:2.0b6) Gecko/20100101 Firefox/4.0b6

I have a 6mbps connection at my office and a core2duo machine. But we have multiple levels of proxies and firewalls and because of that, latency/ping for all internet requests is high, sometimes as high as 1000ms.

Now whenever I have any one tab open in FF which is loading pages, the whole UI and all other tabs literally freezes. But as soon as the loading tab fetches some data (progress bar moves a little) UI becomes responsive for a second and then again freezes while the loading tab waits for more data. FF runs fine even with 20+ tabs with loading done, but as soon as any one of them starts to load any page, all other 19 tabs and whole UI freezes. You can not switch tabs, can not scroll, can not do anything.

I have experienced this issue in more than one machine and more than one configurations. This issue is 100% reproducible every single time whenever a connection is slow (basically with high latency/ping times), makes me think that the http requests are executed synchronously with UI events.

The same thing happens with FF 3.6.x and FF 4.0betas, while I thought per process tabs will solve this, but they didn't. I do heavy web browsing and such an issue is really a deal breaker for me. On exactly the same setup, Chrome works flawlessly for me. While I can not drop FF due to its awesomeness, I have to switch to Chrome again and again whenever I have to work with more than 1 page.

This is a real pain and keeps me thinking what are we doing wrong behind the hoods of such a great web browser. Please look into this. Thanks much!

Reproducible: Always

Steps to Reproduce:
1.Select a high latency (high ping) internet connection, bandwidth can be high, doesn't matter
2.Open 2-3 pages in different tabs, let them load fully
3.Open another tab and try loading any content rich page
Actual Results:  
Observe that a Firefox sends HTTP requests and waits for reply (due to high ping time) that while UI and all other tabs freeze

Expected Results:  
The UI should be interactive while FF waits for such requests

Comment 1

[Jo Hermans]

Firefox 4.0 doesn't have process-per-tab yet, only plugins are running in a separate process. It's being worked on though, but it's for a future release.

Comment 2

[Jitin Sameer]

Oh now I understand that FF4 does not have process per tab, but still this 'freeze' is very irritating. Any idea why is this happening?

Comment 3

[Jo Hermans]

There is still only 1 thread that does the entire GUI. So if 1 page is busy doing something, the others have to wait. It's not completely true that Firefox is waiting on the results of http requests (they're not synchronous), however, there's a lot of things going one (parsing, speculative loading, etc ...), and a lot of things are already happening in parallel. Some will have to wait on each other.

Comment 4

[Patrick McManus [:mcmanus]]

its (at least) your proxy use that is hitting the blocking condition. We'll address that over in bug 769764