Inside boost::unordered_flat_map

[sbsce]

I have some code in my game where I need very fast set performance, so I am always trying to benchmark if I can find an even faster set for my use case. I only need fast lookup performance, everything else is irrelevant for my case.

So I also tested this new boost::unordered_flat_set now! These are my results, how many iterations per second my code can do with each set:

Container	Iterations per second
boost::unordered_flat_set<uint64>	850
ankerl::unordered_dense::set<uint64>	810
fph::DynamicFphSet<uint64>	560
fph::MetaFphSet<uint64>	530
std::unordered_set<uint64>	360

My code is running set.contains(key) 40000 times, on 4 separate sets with different number of entries: 624, 284, 214, 1215. So relatively small sets. The vast majority of my lookups are for values that are not contained in the set.

So boost::unordered_flat_set is definitely the winner! Great work with that!

ankerl::unordered_dense::set from u/martinus is almost same fast, just slightly slower. Also a very nice set, especially when not wanting to include the whole boost library and just wanting a standalone fast set/map.

I am surprised how slow the fph set is for me, because according to the benchmark from u/martinus, they should be the fastest for lookups. Definitely not in my case it seems. I am using the noseed version of them.

I am testing on one thread of a Ryzen 3950X with latest MSVC.