This reminds me of the whitepaper Scalability! But at what cost? http://www.frankmcsherry.org/assets/COST.pdf http://www.frankmcsherry.org/assets/COST.pdf Whi

This reminds me of the whitepaper Scalability! But at what cost? http://www.frankmcsherry.org/assets/COST.pdf http://www.frankmcsherry.org/assets/COST.pdf Which I think is about how single threaded programs are faster than scalable but slow multithreaded systems. I think you might be right and that's why there is ReadWriteLock or RwLock for single writer taking turns. If you have a counter or a data structure you're mutating in every request then you'll hit lock contention.