async-compare

Hmm, those are strange results indeed. I would not be surprised if those measurements were made a year ago. Back then, promises were really slow. But then bluebird came out and changed everything, and many of the other promise libraries followed suit. Most promise libs are now really lightweight (with the only remaining exception being Q). See https://gist.github.com/spion/6990910 ; http://spion.github.io/posts/why-i-am-switching-to-promises.... ; https://github.com/spion/async-compare/blob/master/latest-re... - For example, bluebird (and most other promise libraries today) have 2 to 3 times lower overhead than caolan's async and are comparable to the most hand-optimized raw callbacks.

Some of those "things" you counted are based on generators, which let you to do exactly what you want. Example: https://github.com/spion/async-compare/blob/master/examples/... With promises, generators are not really necessary -- especially if you add arrow function syntax into the mix. https://gist.github.com/spion/8254661 (Note: that particular method in doxbee has long since been refactored to something saner with better separation of concerns :)

That's not throughput. You are running exactly 1 promise in parallel at a time and waiting for it to be resolved. However, on node.js you can have more than 1 client served by your server. For instance, your server could have e.g. 10000 promises/callbacks/generators active at a time. Take a look at how different solutions handle that https://github.com/spion/async-compare/blob/master/latest-re.... The results don't change at all if we for example increase latency of I/O by an order of magnitude - that's why latency is not an interesting metric for this use case. It's pretty intuitive, all the 10000 users will just get their results 9ms later but the fact that we could even handle them in the first place without crashing our server matters. ---------- You are right that for your use-case, pretty much the only thing that matters is what imp

Here are some results from my benchmark [1] results for 20000 parallel executions, 1 ms per I/O op file time(ms) memory(MB) promiseishBluebird.js 1076 76.08 async.js 2634 113.79 promiseishKew.js 2654 123.50 promiseishQ.js 56508 804.21 note: async.js is basically waterfall from https://github.com/caolan/async [1]: https://github.com/spion/async-compare