Java consumes high CPU when idle

[David Lockwood]

I have an application (Vericut 5.3.1) that is written in Java, it uses Java 1.3.07 Runtime. When I start the application, top indicates that it is using about 15% of the CPU. I then run a process in the application and top reports the CPU usage going up to 75% CPU. When the process has finished the application appears idle but top is still reporting 65% CPU usage !! When I run the same application on Windows 2000 I see the CPU usage rise to 99% but when processing has finished it is back to 0% for the Java Virtual Machine. Has anyone any ideas as to what is going on and how it can be cured, ie. back to 0 or near 0% when the application is not processing?

[Steven E. Protter]

Does the Vericut app need Java 1.3.07 Runtime?

A later version of java runtime might clear this up.

Also, make sure you have every patch java 1.3 requires at http://www.hp.com/go/java installed. Failure to do this can result in these and other far more serious issues.

CPU usage of even 100% is not a big problem for Unix, if its for a valid reason. All it means is you are using your machine efficiently.

If you start to swap and have performance problems, then worry.

swapinfo -tam

SEP

SEP

[RAC_1]

Can you use latest java run time environment? If yes try using that and check.

Also are java pacthes applied?

[David Lockwood]

I have the latest pathces for Java 1.3xx and have now noticed that the CPU utilisation as reported by Glance for the Java Virtual Machine does indeed drop to 0.4% when Vericut has finished processing. The problem our users have is that if the Vericut application is open then performance of Catia 4.2.4 is much worse than when Vericut is not open. It does not matter whether Vericut is processing or idle. Any further ideas or experience would be appreciated.