Is System.nanoTime() consistent across threads?

Question

I want to count the time elapsed between two events in nanoseconds. To do that, I can use System.nanoTime() as mentioned here. The problem is that the two events are happening in different threads.

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Since nanoTime() doesn't return an absolute timestamp but instead can only be used to calculate time differences, I'd like to know if the values I get on the two different threads are consistent with the physical time elapsed between the two events.

Erskine

You can can use nanoTime() to calculate the difference from a known time. This can allow you to get a fairly accurate clock. I wouldn't suggest using it for times smaller than a micro-second. – Diathesis

Answer 1

It's supposed to be, but due to buggy kernels or hardware, the answer can be no, at least in some environments.

Manwell

Also, I once got into trouble when setting -XX:AggressiveOpts on Sun JVM lead to unreliable values for System.nanoTime(). – Hilleary

I have no expertise in the matter, but I'll link this highly upvoted answer that suggests this linked blog post is incorrect. – Dunston

As of OpenJDK 8u192, there are no known unresolved bugs regarding this. The last one appears to be bugs.openjdk.java.net/browse/JDK-8184271 – Guerdon