Last year I got a Nokia N9 on Qt Developer Days, it's a great mobile phone, I really like it, but I haven't published any memory measurement results about it yet. In my last post I did WebKit memory profiling on it with Valgrind, but it was all about heap usage. I think a number of persons are interested in the overall memory usage such as peak memory usage, the sizes of the used libraries, etc. During QtWebKit's life-cycle we switch from one library to another, usually because of performance considerations. In the past we do not take too much attention to memory consumption-related topics while switching between libraries, although it would be very vital to keep eye on this area as well.
In this post I would like to share with you one of my latest memory consumption measurements about the heap usage of QtWebKit.
64 bit systems allow allocating more memory, but this extra space has a trade-of: the pointers are grown to 64 bit wide which increases the total memory consumption. Ever wondered about the price of 64 bit? Well, you can find comparisons here about some popular pages on the Qt port of WebKit. Furthermore, we offer some CSS subsystem related comparisons at the end of the post.
A long time has passed since I’ve written, but lately I did some interesting memory consumption measurements on QtWebKit’s WebKit2 implementation. First, let’s talk a little about WebKit2’s process models. There are 2 process models in WebKit (more precisely, there are 3, but for now I don’t take with thread-based solutions into account): the default is the secondary process model, and we can easily switch to shared process model as well. Balazs experienced with a third one called service model which works like a classic server-client connection.
The main focus of my next experiment is yet another allocator called TLSF (Two-Level Segregate Fit). Based on the info published on its website, TLSF has bounded response time, efficient allocation methods which are fast enough, and it has efficient memory usage. Furthermore, the site promises quite good memory fragmentation values. Can it demonstrate all this inside WebKit?
I found Emery Berger's allocator called hoard. Hoard's homepage holds out some promising general qualities (fast, scalable, and memory-efficient) about the allocator, do we need more than this? I tried out how it performs in WebKit.