Would snmalloc (https://news.ycombinator.com/item?id=37851210) help with scalable threading or not? It claims to be better at allocating memory on a producer and freeing on a consumer thread, and "Freeing memory in a different thread to initially allocated it, does not take any locks and instead uses a novel message passing scheme to return the memory to the original allocator, where it is recycled. This enables 1000s of remote deallocations to be performed with only a single atomic operation enabling great scaling with core count."