Why is the asm.js project faster in Chrome and then FireFox?

Question

I ported a game engine project for my university course from C / C ++ to JavaScript using emscripten. The asm.js optimization flag is set, and I am measuring performance. But not surprisingly, Firefox's performance is poor. Although the project works very well in Chrome and Opera. This makes no sense to me, considering that FireFox is a browser that uses asm.js optimization.

This project is a racing game with a race track using SDL and WebGL. Running in Firefox on my laptop profiler shows that the demo is completely connected to the processor, the bottleneck that appears around _SDL_LockSurface () and _TTF_RenderText_Solid (). They are used to render dynamic text by the way.

Nevertheless, in Chrome, the processor almost does not work on the same system. And the performance is similar in Opera. Does this mean that asm.js optimization is not working? Firefox reports have successfully compiled asm.js. So, why does this feedback optimization lead to execution, which at best is half the frame rate? I tested FF version 28 as well as the current nightly build. The demo can be found here, http://www.susurrus.mars-station.com/page7.php?lang=en

Answer 1

I thought about this question for a long time, and I could have an answer for you. Just get rid of it canvas.getContext('2d'). I think asm.js is not your problem.

@BorisZbarsky, , asm.js. , . , getContext, 2D - , .

: http://jsfiddle.net/windkiller/8r3gP/ , 60% .