I just built gnubg on my new quadcore pc with threading enabled (on Ubuntu 7.04). When I run calibrate, indeed it shows on my system monitor that all 4 cores are used. When I run a rollout and I have specified that I want to use only 1 core, there is no problem.
But, when I specify that I want to use 4 cores, the rollout progress dialog opens, but stays at 0 games. In the system monitor it shows that all 4 cores are idle. When I close the progress monitor gnubg stays unresponsive. Some deadlock issue perhaps?