An Interesting Look At the Performance of JavaScript On Mobile Devices 157
First time accepted submitter faffod writes "Coming from a background of console development, where memory management is a daily concern, I found it interesting that there was any doubt that memory management on a constrained system, like a mobile device, would be a concern. Drew Crawford took the time to document his thoughts, and though there is room for some bikesheding, overall it is spot on. Plus it taught me what bikeshedding means."
Re:Mobile web really IS slow! (Score:5, Insightful)
Since this was literally the same link, not just the same story but via a different source, it seems like there could be a pretty simple automated dupe-checker that flags it and tells the editors: a story with the same link was posted in the past N weeks, are you sure you want to post?
Crisis Averted! (Score:5, Insightful)
Re:Typical console developer rant, IMO. (Score:5, Insightful)
The problem is that your baby is not the only thing running on the system. When you waste resources, you do it on behalf of everything else that runs too. Even if your baby isn't doing anything critical when you waste it.
It only takes one selfish programmer to screw up an embedded system. You are he.
More Full Response (Score:5, Insightful)
First off, just as TFA predicts, I'm not going to try to conquer his mountain of facts and experts by presenting a mountain of citations. Instead, I'm going to point out where his conclusions are not supported by his facts and point out his straw man arguments and his attempt to convince us through overwhelming expert opinion.
The straw man: In the article, he presents two scenarios (photo editing and video streaming) and claims that you can't reasonably do those because of memory limitations (on the iPhone/iPad). He then concludes you can't produce useful apps because you can't do those two. I couldn't find any citations of people attempting to do this on mobile using JavaScript. Choose the right tool for the job here. I'll give him these two use cases (and several others: 3D Games, audio processing, etc), however to extrapolate from here that no useful apps can be produced (ever!) using JavaScript is a leap too far.
Next, he spends a lot of time diving into the particulars of garbage collection (GC). I'm going to grant him practically every point he made about GCs. They're true. And, it's true that mobile is a constrained environment and you must pay attention to this. But, this is largely known by developers who are trying to write high-performance JavaScript applications on mobile. Hell, -anyone- writing high-performance apps in any language need to be aware of this. If you allocate memory during your animation routines in a game you're asking for trouble, regardless of the language. So, to me, this part is just a call to pay attention to your memory usage in your apps. This is really useful advice and I will be paying even more attention to the new memory tools available in the latest Google Chrome dev tools.
One of the biggest problems in the rant is the comparison of pure computing performance and his claim that ARM will never be as fast as desktop. I'm going to again grant that this is true. However, this means crap-all for most apps. Tell me: How many apps do you have one your phone that are processor bound? None? One? Two? The vast majority of apps spend their time either waiting on the user or, possibly, waiting on the network. You can write a lot of really useful apps even given constrained processor and memory. Anyone remember the Palm Pre? The TouchPad? Most of those apps were JavaScript and they worked just fine.
This brings me to the point of all this, TFA's author focuses on performance. However, users focus on responsiveness. JavaScript is perfectly capable of producing responsive applications. Sometimes, it takes attention to detail. Nothing is ever 100% free and easy. JavaScript is not a magic solution and those of us who think that JavaScript has a future in mobile app development know this. This is why programmers get the big bucks. Writing mobile apps, you need to be aware of the effects of CSS, memory, processor, responsiveness and more.