WebKit is a very successfull project. It is that in many ways. The code produced seems to very fast, the code is nice to work on, the people are great, the partys involved collaborate with each other in the interest of the project. The project is also very successfull in the mobile/smartphone space. All the major smartphone platforms but Windows7 are using WebKit. This all looks great, a big success but there is one thing that stands out. From all…
This is another post about a modern Linux based performance measurement utility. It is called perf, it is included in the Linux kernel sources and it entered the kernel in v2.6.31-rc1. In many ways it is obsoleting OProfile, in fact for many architectures oprofile is just a wrapper around the perf support in the kernel. perf comes with a few nice application. perf top provides a statistics about which symbols in user and in kernel space are called, perf record…
At the 27C3 we were running a GSM network and during the preparation I noticed a strange performance problem coming from the database library we are using running. I filled our database with some dummy data and created a file with the queries we normally run and executed time cat queries | sqlite3 file as a mini benchmark. I also hacked this code into our main routine and ran it with time as well. For some reason the code running…
I tend to see people doing weird things and then claim that the change is improving performance. This can be re-ordering instructions to help the compiler, attempting to use multiple cores of your system, writing a memfill in assembly. On the one hand people can be right and the change is making things faster, on the other hand they could use assembly to make things look very complicated, justify their pay, and you might feel awkward to question if it…
From my exposure to people deploying QtWebKit or WebKit/GTK+ there are some things that re-appear and I would like to discuss these here. Weird compile error in JavaScript? It is failing in JavaScriptCore as it is the first that is built. It is most likely that the person that provided you with the toolchain has placed a config.h into it. There are some resolutions to it. One would be to remove the config.h from the toolchain (many things will break),…
On the following weekend the Coscup 2010/GNOME.Asia is taking place in Taipei. The organizers have decided to have a strong focus on the Web as can be seen in the program. On saturday there are is a keynote and various talks about HTML5, node.js. The Sunday will see three talks touching WebKit/GTK+. There is one about building a tablet OS with WebKit/GTK+, one by Xan Lopez on how to build hybrid applications (a topic I have devoted moiji-mobile.com to) and…
In general one of the fascinating aspects of WebKit is the focus on just being a Web Content Engine as it can be seen in the Project Goals. One of the results is that one can easily build a Web Browser around it, or embed it into a Mail Client, a Chat Client, or into your application to handle payment in amazon, display Wikipedia or similiar things. On the other hand it is possible to embed native widgets into the…
As this was requested in a comment of a previous post and knowing your kernel helps to write better performing systems here is a small information of how to use the interval timers provided by your posix kernel. What is the interval itime?r The interval timer is managed and provided by your kernel. Everytime the interval of the timer expires the kernel wil send a signal to your application. The kernel is providing three different interval timers for every application….
I hope this post is educational and help the ones among us doing performance optimisations without any kind of measurement. If you do these things without a benchmark you are either a genuis or very likely your application is going to run slower. I’m not going to talk about performance analysis right now but tools like OProfile, callgrind, sysprof and speedprof are very handy utilities. The reason I’m writing this up is that I saw a performance regression in one…
My work on QtWebKit performance came to a surprising end late last month. It might be interesting for others how QtWebKit compares to the various other WebKit ports, where we have some strong points and where we have some homework left todo and where to pickup from where I had to leave it. Memory consumption Before I started our ImageDecoderQt was decoding every image as soon as the data was complete. The biggest problem with that is that the ImageSource…