FULL PRODUCT VERSION :
java version "1.8.0_144"
Java(TM) SE Runtime Environment (build 1.8.0_144-b01)
Java HotSpot(TM) 64-Bit Server VM (build 25.144-b01, mixed mode)


ADDITIONAL OS VERSION INFORMATION :
Linux Ubuntu8G 4.11.0-kfd-compute-rocm-rel-1.6-180 #1 SMP Tue Oct 10 08:15:38 CDT 2017 x86_64 x86_64 x86_64 GNU/Linux


A DESCRIPTION OF THE PROBLEM :
When I run the AnimationTimer class, it runs at an controlled FPS (ranges from 2000 to 30). However when I add the line -Dquantum.multithreaded=false to the run configurations, the problem is solved (FPS remains at around 60).

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
Create a AnimationTimer in your application and measure the frame rate inside the AnimationTimer (1E9/deltaTime). Run the program. See code below.

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The FPS should be around 60 or below.
ACTUAL -
The FPS was very irregular, jumping from 2000 to around 60.

REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
prevTime = System.nanoTime();
AnimationTimer timer = new AnimationTimer() {
@Override
public void handle(long curTime) {
double deltaTime = (curTime - prevTime) / 1E9;
                System.out.println(1/deltaTime);
}
};
timer.start();
---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
-Dquantum.multithreaded=false in run configuration.

SUPPORT :
YES