Kevan Miller wrote: > > > On Mar 6, 2008, at 10:37 AM, Jim Foster wrote: > >> >> Hi Peter, >> >> Thank you for this info! >> >> I took your suggestion and brought myself up to speed on PermGen, >> and a good >> bit of all things related to Java.lang.OutOfMemoryError. >> >> All I can say is that there's certainly a lot more to fine-tuning the >> classloading going on behind the scenes than one would first imagine. >> >> This brings up another question: How do you folks manage this? >> >> What tools would you recommend that I add to my toolbox so that I >> can really >> understand what's really going on beneath the covers? >> >> As I mentioned in my earlier post, this project I am involved with >> will be >> weaving together several applications to be deployed on top of >> Geronimo, so >> sooner or later, fine-tuning performance issues will become a reality. >> >> I'd like to get a handle on such things as early in the development >> cycle as >> possible. > > > Hi Jim, > There are a lot of knobs and switches. However, you can cause as much > harm as good trying to fine tune their settings. My advice to you is > to keep things as simple as possible until you know you have a problem. >
Hi Kevan, Simple is good. I will certainly take your advice. I just know from experience that it best to put a lasso around potential system-related problems like this early in the game...if not they may assume an exponential flight path. Kevan Miller wrote: > > The JVM can print GC statistics to STDOUT. Often I find this > sufficient for getting a broad overview of what's going on. You can > also configure the JVM to create a heapdump on OOME conditions. If you > have a memory leak, you can then analyze the heapdump using a variety > of tools (I like YourKit). There are a number of tools which can also > perform further analysis on runtime data (memory allocations, method > execution, etc). > > Something like the following should work (set max heap and max perm > to suit your environment): > > -Xmx512m -XX:MaxPermSize=128m -verbose:gc -XX:+PrintGCDetails -XX: > +HeapDumpOnOutOfMemoryError > > --kevan > > This is good to know. It's probably too early for me to be thinking of dropping $500 for a profiler like YourKit, but just leveraging the command line options as you suggest should help in keeping things from getting out of control. I appreciate your sharing this. Thanks! Jim -- View this message in context: http://www.nabble.com/Geronimo-v2.1-Plan-Creator-%3D%3E-Deploy-Liferay-4.1.1-tp15437773s134p15901210.html Sent from the Apache Geronimo - Users mailing list archive at Nabble.com.
