[flohofwoe]

It depends how much you are expecting, for instance this WebGL demo does about 15k draw calls per frame on my 2014 MBP with integrated Intel GPU before it drops below 60Hz, that's about 1.8 million WebGL calls per second. On this machine, performance of a native executable is quite similar, so the WASM-to-JS overhead isn't big enough to be noticeable for those 1.8m calls/sec. I know, it's not a really useful benchmark, I guess what I want to say is that for most real-world problems the calling overhead shouldn't matter much, since other things will break down first.

PS: link to demo: http://floooh.github.io/oryol/asmjs/DrawCallPerf.html