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Comment by reitzensteinm | Hacker News Reader

In my experience you can usually achieve near linear speed up. My machine can run 24 threads.

Fair enough on scaling. But 24 is still a lot less than two to three orders of magnitude.

Yes, it is. I'd probably ballpark Clojure at 100x slower than the kinds of low level C# I usually write (gamedev). But threading C#, especially low level imperative C#, is so awful I often don't bother unless it's very important or there's an embarrassingly parallel element (genetic algorithms and simulating sound waves on a 2D grid are two cases I've pulled the trigger where both were true).

This leaves Clojure as 1/4 the overall speed, which seems about right. However that's based on a hugely unscientific gut feeling, because generally I don't touch Clojure if performance matters and I don't touch C# if it doesn't.

By the way, I've implemented persistent data structures on disk for a problem they were particularly useful for. If stalling for a cache miss feels bad, try waiting for an SSD :)

Having to use 24 cores to get to 1/4th of the performance of a single threaded C# application seems particularly awful.

Especially as C# is a relatively pleasant language to use.

It doesn't matter how good threading in clojure is if you don't even need to use it to beat clojure on another language (also: great scaling is pointless if you start so far behind).

Yes, hammering in a nail with a screwdriver is particularly awful. I love using Clojure where it's appropriate, but I'm not in the least bit tempted to use it for game dev.

Could you share an example program that does that?

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