On Mar 9, 2010, at 1:16 PM, Robert Joly wrote: > Mardy wrote: >> >> >> On Mar 9, 2010, at 10:07 AM, Robert Joly wrote: >> >>> Hi guys, >>> I have been investigating XX-7634 which reports high CPU >> utilization >>> by java processes after an ISO install of the commercial >> version (SCS) >>> which uses the IBM JVM. >>> >>> Basically, after an ISO install I'm seeing that *all* the >> java-based >>> processes chew up between 50% and 100% of one processor and >> remained >>> like that for as long as I kept the box up (few hours). >> The processes >>> in question are sipXpage, sipXivr, sipXrelay, sipXconfig, >> sipXrest and >>> sipXprovision. Using jconsole I was able to find that the >> hot thread >>> for each of these services is called 'Attach Handler' >>> (com.ibm.tools.attach.javaSE.AttachHandler.run()) and I also found >>> that I can eliminate the high CPU condition completely on a fresh >>> install by hand-editing the launch command for each of these java >>> processes to add the following property: >>> -Dcom.ibm.tools.attach.enable=no >>> >>> If I add this property then all the processes are >> well-behaved but I >>> do not understand the fundamental reason why the hot thread >> is there >>> in the first place. I'm therefore turning to the Java gods >> that are >>> tuned in to this list to see if they had previous >> encounters with this. >>> >>> Thanks in advance, >>> bob >> >> I would like to know why this issue has all of a sudden shown >> up on the radar. The Attach API and supporting AttachHandler >> thread was introduced, as a result of an upgrade to the IBM >> JVM, back on 2009-11-14 Is it possible that the high CPU >> utilization has been there since then but no one had noticed >> it until now? > > Refresh my memory, will you? Why are we using IBM in the first place?
Initially because it was the only option for supporting one of our customers. In addition, we have discovered that it offers some very attractive memory optimization features not offered by other JVM's that we may need to employ as the number of Java based services increase. > > I do not know when the high CPU behavior started showing up but it was > first reported on 2010-02-10. Also, not every system exhibits the > behavior. For example, our friends at Qantom can I can reproduce the > problem but Al Campbell and Chris Parfitt cannot on their systems. I'm > using a Dell R300 and Qantom is using Dell Optiplex and so do Al and > Chris. I have not identified the ingredient that makes this hot thread > appear and as far as I can tell, IBM does not publish the source code > for their attach implementation. > > The thread seems to be looping around waiting for a semaphore. Please > see the attached screenshot for visual of the stacktrace. > Is this actually causing a problem or is it just a red herring? If it is in fact impacting the performance of the system, then disable it. -Mardy _______________________________________________ sipx-dev mailing list [email protected] List Archive: http://list.sipfoundry.org/archive/sipx-dev Unsubscribe: http://list.sipfoundry.org/mailman/listinfo/sipx-dev sipXecs IP PBX -- http://www.sipfoundry.org/
