[Interest] Extremely sluggish browser performance in Qt 5.5

[Allan Sandfeld Jensen]

On Tuesday 23 June 2015, Till Oliver Knoll wrote:
> > Am 23.06.2015 um 03:14 schrieb John C. Turnbull <ozemale at ozemail.com.au>:
> > 
> > It seems that the "problem" exists in 5.4.2 as well so it's definitely
> > not a regression.
> 
> Sorry, just a shot into the blue here. Maybe the problem has to do with how
> Qt interacts with the underlying network stack? IPv6 setup, maybe?
> 
> And does the problem also occur on other (Window) machines? A firewall
> maybe which gets overly "busy" with that "unknown browser"?
> 
> What about other Qt networking (example) apps? Wasn't there once a simple
> FTP example (I guess that's gone though, since QFtp doesn't exist anymore
> in Qt 5 - or does it?)?
> 
> Or that QML "Flickr Image Viewer" that I have in mind? Do those Qt network
> applications exhibit the same extreme slowness (which would hint at a
> problem somewhere in QAbstractSocket and friends maybe)?
> 
> Are you in a "corporate network"? What if you run the application in
> another network (preferably on the /same/ computer)? Are you sure the
> other browsers don't use a (default system) proxy which would bring the
> network packets "on the fast lane"?
> 
> 
> My best bet is a problem with IPv6, the rest above sorted in "increasing
> esotheric order"...
> 
Remember you can't compare to other network-using Qt applications, since 
QtWebEngine is using Chromium's network stack, not Qt's. So the question when 
is the Chromium stack doing something wrong, and what is Chrome doing 
differently to not hit that issue.

`Allan