1566322 - Firefox takes a long time to load pages

Status: RESOLVED INCOMPLETE

(Core :: Networking: DNS, defect)

Description

[Asif Youssuff]

User on reddit complains that they need to open a site in multiple tabs to open a page.

It seems like a nasty performance issue.

See profile here: https://perfht.ml/2Lgpc5r

Original report here: https://www.reddit.com/r/firefox/comments/cbw0yl/forced_to_open_multiple_tabs_for_1_page_just_to/

Comment 1

[Liviu Seplecan]

Hi @Mike, I cannot reproduce it. Additionally, there is a profile report and a "Reddit" support - from the discussions appears that multiple scenarios have been tried where other users encountered the same problem. In the end, the issue still occurs. Can you please give us a hand with that?
I will set a component, if isn't the right one please fell free to change it.
Thanks.

Comment 2

[Mike Conley (:mconley) (:⚙️)]

The Profile suggests that we're waiting for the networking stack to complete something - however, the Profile is missing a bunch of information, like which add-ons the user has installed, and it's also missing threads like the DNS Resolver and the Socket Thread from the profiler, so I can only infer from the Network pane.

What I suspect is happening here is that we're taking a long time doing DNS requests. Load 1, for example, takes about 12s to make the DNS request, which is really really strange.

If the computer that's exhibiting this behaviour is portable, I'd be very interested in knowing whether or not the user experiences the same thing if moving to a different network.

I'm going to put this in Core :: Networking: DNS for now.

Comment 3

[Michal Novotny [:michal]]

We need a log to verify that it's a DNS issue (https://developer.mozilla.org/en-US/docs/Mozilla/Debugging/HTTP_logging)

Comment 4

[Honza Bambas (:mayhemer)]

Would be nice to diagnose with backtrack.

Comment 5

[Asif Youssuff]

Sorry, the original reporter never responded to my request for a HTTP log.