What is the overhead of the spectre mitigations? I read a PhD dissertation showing that v8 suffers a 20% overhead in practice. People can sugar those numbers, b

What is the overhead of the spectre mitigations? I read a PhD dissertation showing that v8 suffers a 20% overhead in practice. People can sugar those numbers, but I wouldn't expect another userspace-emulator-like program to behave differently. Is this number in the ballpark for wasmtime?