Asm.js Gets Faster

mikejuk writes "Asm.js is a subset of standard JavaScript that is simple enough for JavaScript engines to optimize. Now Mozilla claims that with some new improvements it is at worst only 1.5 times slower than native code. How and why? The problem with JavaScript as an assembly language is that it doesn't support the range of datatypes that are needed for optimization. This is good for human programmers because they can simply use a numeric variable and not worry about the difference between int, int32, float, float32 or float64. JavaScript always uses float64 and this provides maximum precision, but not always maximum efficiency. The big single improvement that Mozilla has made to its SpiderMonkey engine is to add a float32 numeric type to asm.js. This allows the translation of float32 arithmetic in a C/C++ program directly into float32 arithmetic in asm.js. This is also backed up by an earlier float32 optimization introduced into Firefox that benefits JavaScript more generally. Benchmarks show that firefox f32 i.e. with the float32 type is still nearly always slower than native code, it is now approaching the typical speed range of native code. Mozilla thinks this isn't the last speed improvement they can squeeze from JavaScript. So who needs native code now?"

Comments

Re:"So who needs native code now?"

[phantomfive]

Correct this to any real programmer. I'm tired of web designers being colluded with actual programmers, scripting isn't programming.

Heh....typing isn't programming. If you aren't connecting patch wires on an accumulator bank, it's not worth doing. You get more efficiency that way too!

Re:Or anything running in a VM

[zippthorne]

Another question is why we need to duplicate an entire operating system to encapsulate applications. If you have 100 things that need to run on a machine why should you need to also run 100 entire operating systems? Something is wrong with the way we're designing servers.