Thank you @Konstantin-Tokarev This explanation means a lot. This helps us to understand that we are using older version of Qt WebKit and which is not really efficient.
At this moment of time, we don't have a plan to update to the latest version. We will have to find a work around in the application to manage the situation.
Does it mean that you cannot change any bits of software in your system and you are limited to workarounds on the side of web page? If so, it's really sad situation.
If you are able to change software, you are strongly adviced to use QtWebKit 2.3.4, or at least give it a try.
@Konstantin-Tokarev Yes, we have been trying to understand who consumes the lot of CPU and why. When I did profiling using gprof/perf tools, I can find out that which function in my application consumes a lot, but that does not root in to the framework, which is webkit. Do you recommend any method which I can profile the framework side as well?
Don't use gprof. This tool claims to measure time spent in functions, but in fact measures totally different thing. And, as you've already discovered, it can only profile code which was rebuilt with -pg flag.
As for perf, it is decent tool. On older systems oprofile can be used. Make sure that your QtWebKit library is not stripped
And even if we find issues in the framework, at this moment we are not in a position to upgrade the system. So we will identify the work around and live with it ( Already found couple of work around solution, which I will be sharing it in a while here )
I have no idea what do you mean here, and I don't really want to be in your shoes. (/me once had to reverse engineer and then binary patch 3rd party kernel driver with no source code, but at least there were no problems with updating target system)
Reason for asking such question is,
Someone might have faced similar problem and might have the ready solution. Instead of I spending lot of time in exploring, researching, debugging, etc, I could post it here to know if someone knows about it. However, in parallel to posting this question, I have been doing things in parallel if in case I don't get the answer. For this post, you being a legend on webkit, you have mentioned that it could be a problem of webkit version that we use, which makes sense and unveils the root cause.
I'm far from being legend, and there may be other reasons of high CPU consumptions, maybe several factors at once. It can be that WebKit just doesn't have enough memory to process page, and system is thrashing (you'll see high sys usage in top then).
When I touch the report, does Qt Web Kit renders the whole web page again?
If you are not using QWebSettings::TiledBackingStoreEnabled and are not using accelerated composting on QGLWidget viewport, and are not using QWebPage::setPreferredContentsSize, then QtWebKit definitely reners whole page again after scroll. It doesn't redraw old pixel, but it performs whole rendering procedure with QPainter being clipped to update region. It may easily be a bottleneck if page is complex