zamadatix 2 days ago

Go's int defaults to 64 bits on a 64 bit machine while C/Rust/Java are all defaulting to 32 bit on the author's machine.

Editing the code and running local to get a difference factor, it looks like the same Go code with int takes 1.5x the amount of time as the int32 code on my machine. That puts it ~right next to Java (assuming the perf change maps 1:1). Remove the GC and it comes in ~right next to C++.

Looking at the compiler assembly output on Godbolt it's fun to see all the extra panic info and checks Go adds before going to the loop whereas the C just segfaults from blasting forward anyways, sometimes with no detail.

Anyways, that's why I don't like these types of "benchmarks" (micro tests made into a media post). By the time someone actually looks into them to see what's up everyone has already seen the results and moved on.

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iambvk 1 day ago

Thanks for this information. I wasn't aware that using 64-bit ints makes such a big difference in performance. Thank you.

zamadatix 1 day ago

Usually less on computation performance (often identical or very close to in raw cycle count for the operation) but more on cache/memory performance. The way that maps is platform specific of course.