A nice thing about this is that it keeps the collections happening while no users are waiting. Before seeing this I figured what they'd do for throughput might

A nice thing about this is that it keeps the collections happening while no users are waiting. Before seeing this I figured what they'd do for throughput might be more of a Java/C#-like compacting young gen collection, which still introduces (short!) pauses. Also, fun wrinkle: seems like occasionally, wrapping a slowish, mostly-self-contained, garbage-heavy function call in a goroutine could be a useful hint to this collector. It seems like it's only useful when 1) a transactional GC on the calling thread or full GC would really be slower (e.g. calling thread keeps lots of live data so GC on it takes more work), and 2) the launch/communication costs (expect at least µsecs) are small enough relative to gains. But interesting it's even possible for it to work out that way.