>After reaching that initial 10ms goal, we re-aimed and set our target on something more ambitious. Namely that a GC pause should never be longer than 1ms. Starting with JDK 16, I’m happy to report that we’ve reached that goal too. ZGC now has O(1) pause times. In other words, they execute in constant time and do not increase with the heap, live-set, or root-set size (or anything else for that matter). Of course, we’re still at the mercy of the operating system scheduler to give GC threads CPU time. But as long as your system isn’t heavily over-provisioned, you can expect to see average GC pause times of around 0.05ms (50 µs) and max pause times of around 0.5ms (500 µs).

Very impressive and well done. Should Azul be worried?