[temp123789246]

I wonder how much of a perf hit a normal multithreaded Unix application would take because of this model. Are there any data points around the multi-threading perf here?

[syrusakbary]

Usually it adds an extra 10-25% of overhead when the WASIX program uses systemcalls that require unwind/rewind functionality (this is for fork and subprocesses mainly, the multithreaded ones doesn't require asyncify and as such should not experience a performance hit)

[chatmasta]

I believe JS workers are actually implemented as threads, so the performance overhead might not be as bad as you'd expect.