Why is the mobile web slow?

Post by pkolaczk » Mon, Jul 15, 2013, 1:55 PM UTC

kybernetyk wrote: post #4

> Objective-C doesn't use methods like Java/C++/C#, it uses messages like Smalltalk. This effectively means it always performs late binding and invoking a message is REALLY slow in Objective-C. Well, "always" is a little wrong. The first time a message is passed and the bound method is called by the runtime is significantly slower (~4x slower than a virtual method call in C++). But then this message/method pair gets…

Post by kalms » Mon, Jul 15, 2013, 2:10 PM UTC

mr_luc wrote: post #6

The takeaway I got from this: DOM reflows are the major unsolvable source of perceived slowness. Cool. So, in an app where you avoid reflows, is mobile web fast? Why or why not? How avoidable are reflows? Can anyone point me to any articles that talk about this specifically, or benchmarks that make this concrete? (I vaguely recall benchmarks that covered reflow, but it's a vague memory).

Post by invalidname » Mon, Jul 15, 2013, 2:11 PM UTC

chrisdevereux wrote: post #2

> Don't allocate when you need fast performance. This is good practice regardless of whether you are using a GC since allocation/deallocation of memory are slow operations (in fact game programmers NEVER allocate during game level execution). > This isn't really hard, you just make sure that while you are performing an animation or within a game level you don't make any allocations. The GC is unlikely to kick in and…

Post by [deleted] » Mon, Jul 15, 2013, 2:14 PM UTC

ohwp wrote: post #14

mr_luc wrote: post #6

The takeaway I got from this: DOM reflows are the major unsolvable source of perceived slowness. Cool. So, in an app where you avoid reflows, is mobile web fast? Why or why not? How avoidable are reflows? Can anyone point me to any articles that talk about this specifically, or benchmarks that make this concrete? (I vaguely recall benchmarks that covered reflow, but it's a vague memory).

Maybe this will help: https://developers.google.com/speed/articles/reflow Edit: ah, posting the same link at the same time... But I think the best tip is: be shallow. A lot of things trigger reflow but DOM-depth is causing slow reflows.

Post by CountHackulus » Mon, Jul 15, 2013, 2:24 PM UTC

dougk16 wrote: post #9

"They can also reallocate elements into the stack frame rather than heap when they detect specific allocation usage." I've always been interested in whether this is done in various managed languages. Since I never know the answer, one pattern I've taken to is to allocate memory in static const/final fields that I would normally put on the stack in C, instead of doing a heap allocation to a variable whose scope is com…