Using Rust to Scale Elixir for 11M Concurrent Users

When the list is small the performance looks pretty great measuring between 0.008𝜇s and 288𝜇s. Sadly, when the size tested was increased to 250,000 worst-case performance increased to 27,000𝜇s, which was five times faster than our custom List implementation but still not fast enough. The OrderedSet was a wrapper around a list of Cells, inside each cell was a small ordset: the first item of the ordset, the last item of the ordset, and a count of the number of items. Insertion of an item at the end of a 250,000 item list dropped from 27,000𝜇s to 5,000𝜇s, five times faster than raw ordsets and 34 times faster than the naive List implementation.

Source: blog.discordapp.com