Bug 398735

Summary: Falkon: Loading Some Pages Freeze Entire Browser
Product: [Applications] Falkon Reporter: williamniu
Component: generalAssignee: David Rosca <nowrep>
Status: REPORTED ---    
Severity: normal CC: jurajoravec, magiblot, mochobb
Priority: NOR    
Version First Reported In: unspecified   
Target Milestone: ---   
Platform: Chakra   
OS: Linux   
Latest Commit: Version Fixed/Implemented In:
Sentry Crash Report:
Attachments: Link to screen recording of the issue

Description williamniu 2018-09-17 00:00:08 UTC 
When loading a site such as a document in Google Docs (example: https://docs.google.com/document/d/1t-mgo8ZdPx4ajWafnNXyeEzqVBoTvR-S17uyXpEO2WE/edit?usp=sharing), Falkon loads the page, but after a second, it tries to repeatedly reload the page. The reload icon flashes in the favicon area of the page which freezes all windows of the browser. Only about 15 seconds later will the page stop refreshing and I am able to interact with any of my open tabs. This has been a great hinderance to what I would otherwise consider to be a great browsing experience. Please look into this issue. Thanks!
Comment 1 Juraj 2018-09-18 15:56:23 UTC 
The mentioned site works fine for me.
Can you add information about Falkon and QtWebEngine versions ?

I am using:
> Application version 3.0.1
> QtWebEngine version 5.11.1
Comment 2 williamniu 2018-09-29 23:26:19 UTC 
I have the same application version but my QtWebEngine version is 5.11.2.
Comment 3 magiblot 2018-11-01 15:28:20 UTC 
Created attachment 116024 [details]
Link to screen recording of the issue

The link in the first post cannot be used to reproduce the issue because it only happens when you are in edit mode. I have in fact made a capture of it. I wouldn't describe it as Falkon trying to reload the page though.

In the enclosed video, the page ends up loading pretty quick but it often takes a long time just like the reportee describes.
Comment 4 magiblot 2019-03-28 13:37:35 UTC 
I have finally found the cause of this: falkon freezes because it is repeatedly accessing the disk in order to write to the following file:

> ~/.config/falkon/profiles/default/browsedata.db

Proof: moving said file to a tmpfs location (e.g. /dev/shm) and placing a link in the original place solves the issue, although it should be restored before powering the machine off or it will be lost.

To track down the issue, I used the tool suggested here: https://unix.stackexchange.com/a/34175
Comment 5 magiblot 2019-03-28 13:59:36 UTC 
A simpler website which also suffers from this issue is: https://bit.ly/2FIgvwN

I experience accesses to the hard drive each time I change slides in that page. It is then when the reload icon flashes.

It seems that the issue can also be avoided by using private browsing.

Thank you.
Comment 6 mbb 2019-07-03 16:18:54 UTC 
A simple way to workaround this is to cache ~/.config/falkon using vmtouch. I also installed vmtouch-systemd and set that folder in /etc/vmtouch.conf for convenience. It works very well and performance has increased greatly.