How about this: K is an interpreted language, but your whole program's source code plus the interpreter plus the whole database engine fits inside your server's L1 cache, so K programs tend to be faster than their C equivalents (in addition to all the array operations being highly optimized).
And you don't get to waste time scrolling, your typical module's code fits on your single screen.
I know it's all been said before, but the performance take here is somewhere between misleading and wrong. K runs code quickly for an interpreter because it has a simple grammar and a small number of types, but you don't get up to compiled speed just by reducing overhead, so it will lose to C, Javascript, or LuaJIT in this regard. If you can concentrate the program's work in a few operations on large arrays (not always possible), then K might beat idiomatic C. I don't think I've ever seen an example of this.
Anything about the L1 cache and K is just wrong, usually. At 600KB the K4 database engine is much too large to fit in L1 (K9 from Shakti is somewhat smaller but still a few times too large). And L1 instruction cache misses aren't a bottleneck for other languages, so there's little benefit in reducing them even to the extent K does it.
> but your whole program's source code plus the interpreter plus the whole database engine fits inside your server's L1 cache, so K programs tend to be faster
Is that really the bottleneck? I've done quite a lot of profiling on high performance code and I've almost never hit a bottleneck in the instruction cache. Data access bottlenecks or branching hit performance harder and sooner than instruction fetching.
> And you don't get to waste time scrolling, your typical module's code fits on your single screen.
How much of the time you save scrolling is spent on decoding an array of symbols and remembering what those symbols are?
And you don't get to waste time scrolling, your typical module's code fits on your single screen.