alt Hacker NewsI did a microbenchmark recently and found that on node 24, awaiting a sync function is about 90 times slower than just calling it. If the function is trivial, which can often be the case.
If you go back a few versions, that number goes up to around 105x. I don’t recall now if I tested back to 14. There was an optimization to async handling in 16 that I recall breaking a few tests that depended on nextTick() behavior that stopped happening, such that the setup and execution steps started firing in the wrong order, due to a mock returning a number instead of a Promise.
I wonder if I still have that code somewhere…
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> I did a microbenchmark recently and found that on node 24, awaiting a sync function is about 90 times slower than just calling it. If the function is trivial, which can often be the case.
I dabble in JS and… what?! Any idea why?
Here is my test harness and results: https://github.com/conartist6/async-perf
that sounds way off. there is a big perf hit to async, but it appears to be roughly 100 nanoseconds overhead per call. when benchmarking you have to ensure your function is not going to be optimized away if it doesn't do anything or inputs/outputs never change.
you can run this to see the overhead for node.js Bun and Deno: https://gist.github.com/billywhizz/e8275a3a90504b0549de3c075...