But he isn't benchmarking web server concurrency because he is doing a single curl
$ time curl http://localhost:8000
165580141
real 0m0.016s
user 0m0.007s
sys 0m0.005s
So he is running the Fibonacci (40) once with the web server. The only concurrency / parallelism that is happening is in the recursive Fibonacci algorithm. I stand by my contention that the Fibonacci algorithm is a very poor test of concurrency / parallelism.
I stand by my contention that he should have implemented an algorithm that could be solved in concurrent pieces and then benchmarked node.js against his favorite language. If the algorithm cannot be parallelized effectively, it doesn't matter how many tasks you spawn to solve it (cooperative or otherwise), the algorithm's dependencies will cause all the tasks to block and effectively serialize their execution.
I'm referring to the original post (http://teddziuba.com/2011/10/node-js-is-cancer.html), which did test concurrency. The Haskell guy missed the point entirely and seems to have given up after Haskell is shown to memoize his function.
I stand by my contention that he should have implemented an algorithm that could be solved in concurrent pieces and then benchmarked node.js against his favorite language. If the algorithm cannot be parallelized effectively, it doesn't matter how many tasks you spawn to solve it (cooperative or otherwise), the algorithm's dependencies will cause all the tasks to block and effectively serialize their execution.