Accelerate Your JBoss Enterprise Middleware - Red Hat Summit

Accelerate Your JBoss Enterprise Middleware –Java Virtual MachineJavaJavaVirtualVirtualMachineMachine●The Sun JVM, as well as OpenJDK, requires the following option, passedon the command-line, to use large pages:● -XX:+UseLargePages● There is also something in Linux called “Transparent huge pages”.● Transparent huge pages allows the operating system (Linux) toevaluate memory usage of processes and dynamically move fromregular pages to large pages (consolidates many 4k pages into a largepage).● For some workloads this may be sufficient. For other, the staticconfiguration, and usage will be better.● If you have transparent huge pages turned on in the Linux kernel, youshould not specify the JVM argument to use large pages. Only if youopt for the static configuration, which I'll walk through next.● From my testing so far, I would not recommend having bothstatically defined large pages, and transparent huge page support onat the same time!●To turn off transparent huge pages, you can set a boot parameterin grub.conf as follows: