#I just tried Robocode on J2SDK 1.4beta3/Win2K, it's quite jerky... #Hotspot sux? Great multithreading is supposed to be one of Java's #(and Hotspot's) promises. Oh well at least it did not crash or #anything. #
To take advantage of the HotSpot JVM, you really need to do a lot of experimentation, and tweaking to get the right combination of switches (the -XX: switches).. As an example, the HotSpot JVM has a generational heap which affect memory, and garbage collection alot. Basically, new objects are placed in the nursery (aka eden, as in the Garden Of Eden) where little garbage collections happen (this leans on the fact that most objects are shortlived). Objects that have outlived the nursery are transfered to the global heap. Tweak the generational heap value; if you do not have an optimal balance between the two(2) heaps, your app will end up performing horribly. http://java.sun.com/docs/hotspot/VMOptions.html I asked the HotSpot Team at the HotSpot session Q&A at JavaOne 2001 about any rule of thumb on what to set the heap size, and the answer I got was "there isn't.. you need to experient, and find the appropriate values for your specific application". From my experimentation with our backend applications (Weblogic/JDK 1.3.1), I've found considerable performance gain at nursery == 30% global heap size. BTW HotSpot for Linux, and Solaris both come with client and server systems while the Windows version only come with the client system. http://java.sun.com/docs/hotspot/PerformanceFAQ.html#3.5 stay cool. jeff -- -- Jeff Gutierrez Mapua Online! http://www.mapua.org http://www.mapua.com http://www.mapua.net Pinoy Ako! May reklamo? _ Philippine Linux Users Group. Web site and archives at http://plug.linux.org.ph To leave: send "unsubscribe" in the body to [EMAIL PROTECTED] To subscribe to the Linux Newbies' List: send "subscribe" in the body to [EMAIL PROTECTED]
