CPU spikes every 7-10 seconds while debugging JBoss

Hi all,

On two occasions (different companies and code bases) I've run into a problem where the JBoss process I'm debugging spikes the CPU every 7-10 seconds. When I disconnect the debugger the CPU spikes disappear. This occurs when there is no external activity to the JBoss server; for example, HTTP requests. When I do try to use a servlet in JBoss while debugging the CPU spikes to just about 100% continuously.

OS X 10.5.5, MacBook Pro, lots of free memory and hard drive space
IDEA: 7.0.3, 7.0.4, 7952, 8823--all show the CPU spikes
-Xms384m -Xmx600m -XX:MaxPermSize=200m
Java 1.5.0_16 (and earlier 1.5.0)
JBoss 4.5, -Xms384M -Xmx512M -XX:MaxPermSize=200m (sufficient, I believe, for our needs--at least it has been)
also Java 1.5.0_16 (and earlier 1.5.0)
using remote debugging, JBoss started up via the command line

When this happened at a previous company with IDEA 5 I started using one of the IDEA 6 EAP builds and the problem went away. I tried that now but the problem persists.

Any thought on why the debugged app would periodically spike the CPU during debugging? I've run everything (I could think of, at least) in log4j DEBUG mode and can't see any culprits.This problem has just started and I can't think of what I've changed in my environment.

Thanks,
Kevin Monahan

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Do you have any method breakpoints set?

Kevin Monahan wrote:

Hi all,

On two occasions (different companies and code bases) I've run into a problem where the JBoss process I'm debugging spikes the CPU every 7-10 seconds. When I disconnect the debugger the CPU spikes disappear. This occurs when there is no external activity to the JBoss server; for example, HTTP requests. When I do try to use a servlet in JBoss while debugging the CPU spikes to just about 100% continuously.

OS X 10.5.5, MacBook Pro, lots of free memory and hard drive space
IDEA: 7.0.3, 7.0.4, 7952, 8823--all show the CPU spikes
-Xms384m -Xmx600m -XX:MaxPermSize=200m
Java 1.5.0_16 (and earlier 1.5.0)
JBoss 4.5, -Xms384M -Xmx512M -XX:MaxPermSize=200m (sufficient, I believe, for our needs--at least it has been)
also Java 1.5.0_16 (and earlier 1.5.0)
using remote debugging, JBoss started up via the command line

When this happened at a previous company with IDEA 5 I started using one of the IDEA 6 EAP builds and the problem went away. I tried that now but the problem persists.

Any thought on why the debugged app would periodically spike the CPU during debugging? I've run everything (I could think of, at least) in log4j DEBUG mode and can't see any culprits.This problem has just started and I can't think of what I've changed in my environment.

Thanks,
Kevin Monahan


--
Martin Fuhrer
Fuhrer Engineering AG
http://www.fuhrer.com

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I did, although unintentionally! I must have had an inaccurate mouse click at some time. Removing the method breakpoint resolved the problem. Thanks much for suggesting that I look at that pane of the Breakpoints dialog! I had removed all line breakpoints but didn't check for other types of breakpoints as I rarely use Exception, Field or Method breakpoints.

Again, thanks for the suggestion!
Kevin

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