[criticaltinker]

Adding to this great comment with my own experience at work where we extensively use signal processing and time series compression algorithms to visualize large amounts of biological signals in the browser.

WebAssembly is less than 10%-20% slower than native code in our benchmarks and tests for algorithms like fast wavelet transform and bit packing.

WA allows us to aggressively optimize ahead of time when compiling, and be less sensitive to JS engine performance pitfalls around JIT optimization and garbage collection.

[pistachiopro]

Throwing in my data: for physics simulation code, WASM vs native was identical, provided the native code was compiled with automatic SIMD optimizations disabled. On the one hand, that speaks well of the idea of web assembly, on the other, disabling SIMD is highly artificial. It's good to see basic SIMD being made standard, though the 256-bit wide SIMD instructions are still being finalized, and those will be necessary to really have a chance at evening out performance vs. native.