Hello again, I was forced to use a profiler to see what's wrong and it appears that a method in an external random number generator library (CERN Mersenne Twister library) was the culprit. The Poisson random number function would fall into a long loop for small Lambda parameters. I had modified the lambda to a small number in my simulation data files (not in the code). Removed the function and used my own simple code and I now got a wooping 100x simulation speed.... Sorry for taking your time guys [image: image.png] On Fri, 5 Mar 2021 at 15:18, Robert Zupko <[log in to unmask]> wrote: > Mac: > > I’ve seen that before when a new Java patch has been installed. We’re > there any updates to the system? > > Regards, > Robert Zupko > > > On Mar 5, 2021, at 09:46, Mac Sarmady <[log in to unmask]> wrote: > > > > Hello > > > > I am using Java 11 to run mason simulations. A few weeks ago my > simulations were reasonably fast (crowd simulation with a few hundreds > agents). > > > > Then I had a pause and when I ran the simulations a few weeks later they > are extremely slow (perhaps between 4 to 10 times?) > > > > - Has anyone encountered such a thing on his/her JVM and simulations? > > > > - Is there a benchmark on any of the mason examples that I can test and > see whether the problem is from the installation or something inside my own > code (I don't remember changing it in the period)? > > > > Regards, > > Mac >