Poor performance under high load

[Jason A. Donenfeld]

Hi Max,

Thanks for doing this test; that's super useful. What you're
describing is definitely not expected behavior. Think you could try
the same test with 0.0.20180620 and 0.0.20180625? In particular, I'm
interested to know whether a performance _regression_ introduced in
0.0.20180620 actually results in the correct behavior.

Meanwhile, we (CC'd) have been working on implementing a lockfree
queue structure, but we haven't seen any configurations yet where this
actually results in a performance improvement.

Care to share your benchmark scripts? Sounds like this could be really
useful for directing our optimizations.

Jason