On Thu, Oct 22, 2009 at 10:04 PM, Ron Wells <[email protected]> wrote:
> ?? maybe not understanding... not failing just eating up machine .. IFL > just about pinged out on usage . with one app.WAS with the Java But if your WAS application has work to do and the CPU is there, would you expect something else than that it uses what it can get? Starting a Java application can use a *lot* of CPU because the optimizer and JIT (re)compile classes as CPU time permits. This can sometimes make it continue using a lot of CPU cycles even after the application server claimed it is ready and waiting for work. Without instrumentation it does get hard because you don't have a record of what happened. But I doubt this was your favorite way to approach the problem without tools... ;-) First you need to check that it really is the application using the CPU, and not something else. So does it really get the resources from z/VM or is something holding it back there? You also make sure you don't swap excessively. When it really is the application using it, you could use "ps" to see the total accumulated CPU usage per process / thread, take a javacore dump and see what were the big chunks. When you find that the garbage collection is the big chunk, then run the logs through a GC analyzer to see if someone seriously underestimated the application memory requirements. The other thing to look out for (especially since you say they are just getting started) is that anything that you deploy on WAS will take resources, even when you don't use it. Sometimes developers start with deploying all kind of sample applications to learn. Rob -- Rob van der Heij Velocity Software http://www.velocitysoftware.com/ ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
