I am running a virtual server with Ubuntu 10.04LTS that shows 4 cores available in top and nmon. I have attempted several java applications that run multi-core with no problem on a windows box. To be specific, as a sanity test I am attempting to run the Java 7 Fork/Join sample at: http://www.javacodegeeks.com/2011/02...ogramming.html which has a single-thread and multi-thread example.

Whenever I run ANY multithreaded Java application in Ubuntu, It thrashes one of the cores and leaves the remaining 3 undisturbed. How do I get Ubuntu and Java to play nice with these apps and give them the multi-core loving I so desperately want them to enjoy?

Since you said you are running a virtual server, what are you using to do this? VMware? VirtualBox? You may need to enter the settings of said program and make sure that it has the correct permissions to use all cores of your CPU.

The VM is on Rackspace. Interesting thought... They may be showing multiple cores, but on lower timeshare/ram servers, they may truly only be exposing one. I'll experiment and report.