Now what about shutdown?

So far we've seen large jitter in shutdown times - varying from 3 to well over 10 seconds. Shutdown is a really hard case for optimization as we have no idea what threads are going to be woken up and perform work when we killall9, and thus it's extremely unpredictable.

We so try to send a sync() as early as we possibly can to the system to remove some of this load, which seem to help.