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AXcrystallis
AXcrystallis
Known Participant
July 19, 2011
Question

High CPU usage in system running nothing !!!

  • July 19, 2011
  • 2 replies
  • 2174 views

I have a Windows Server 2008 Enterprise SP2

with Coldfusion 9.01 Standard Developer edition

and MS-SQL 2008 Developer database server.

I use it mostly for testing and development. The system was working just fine, but suddenly it started timing out queries, slowing down etc.

Even when nothing (no application, no schedule task, no sites etc) runs in the system I noticed that it uses 25% - 40% of system CPU.for various period of times. Sometimes for some minutes, sometimes for many hours or days. After this period the CPU falls to 0%-1% again and the system works fine. After some minutes or hours the CPU goes again to 25%-40% for no reason.

When I disabled the service "ColdFusion Application Server" then the CPU goes to 0%-1% and the system works fine permanently.

I say it again, in the system there is no site, no schedule task, no datasource.

In the past all I had in the system was a group of Scheduled tasks. So I deleted all scheduled tasks, I even deleted a datasource to a database I had. So now there is no CF code running in the system. So then why the service "ColdFusion Application Server" uses 25% - 40% of CPU resources ????

Any help ???

In the image below you see the use of CPU (about 25%) and how suddenly it falls to 0%.

In the image below you see the processes in Task Manager.

As you see JRun used 40 minutes of CPU Time in last 7-8 hours in a system that runs nothing !!!!

Any ideas ?????

Anastassios

    This topic has been closed for replies.

    2 replies

    C
    carl type3
    Legend
    July 19, 2011

    Greetings,

    With CF9 dev edition you should be able to run CF monitor. Perhaps that will provide some clue as to JRun consuming CPU resources? You could run CF Monitor when the system is acting normally and when it is CPU bound then compare difference.

    CF Monitor is available from CFadmin.

    Monitoring Settings > Server Monitoring > Settings > tick Enable Monitoring

    Server Monitor  > Server Monitoring > Server Monitor > Launch button > Start Monitoring (top middle button).

    All the best with that, Carl.

    Charlie Arehart
    Community Expert
    Charlie ArehartCommunity Expert
    Community Expert
    July 20, 2011

    I don't know: with no requests running, I can't imagine what much useful info the server monitor would show, which is why I didn't recommend it. Indeed, it may be that when it's at high cpu like was reported, the user may not even be able to get into the server monitor.

    Just some additional thoughts. You know I'm a fan of the tool.

    /charlie

    /Charlie (troubleshooter, carehart. org)
    Charlie Arehart
    Community Expert
    Charlie ArehartCommunity Expert
    Community Expert
    July 19, 2011

    Yes, Anastassios, it's not as unusual as you think.

    I would recommend that you look at the CF runtime (or JRun) logs. If on CF Standard or Enterprise Server, look in \runtime\logs. If running Enterprise Multiserver, look in \logs. In either case, look for the most recently written "out" log (or around the time of the problem). I suspect you're having outofmemory errors (look for that string, specifically, no spaces).

    Now, don't assume that if you get them that it means you need to "add more heap". In fact, you may be better suited by using less. The question depends on the error you get. If it says "heap", then perhaps yes you need more heap (but maybe instead something us holding heap longer than it should--yes, even when no requests are running, like sessions, query caches, application scope, etc.)

    But the outofmemory error may say something else, like "unable to create new native thread", or "swap space", or "permgen", and so on. These do NOT mean you need to add more heap, and may mean you'd be served well by lowering it.

    There are far too many permutations to elaborate. I started a series of entries on the subject:

    CF911: Lies, damned lies, and when memory problems not be at all what they seem, Part 1

    http://www.carehart.org/blog/client/index.cfm/2010/11/3/when_memory_problems_arent_what_they_seem_part_1

    I never finished it, but you may get value from what is there to start it out.

    I will say that if you are still stumped and need help solving this, this sort of CF server troubleshooting is what I do for a living and I'd be happy to help. I can often solve such problems in less than an hour or two. More at www.carehart.org/consulting/. In any case, I hope the above is enough to get you started on your own.

    /charlie arehart

    charlie@carehart.org

    Providing fast, remote, on-demand troubleshooting services for CF (and CFBuilder)

    More at http://www.carehart.org/consulting

    /Charlie (troubleshooter, carehart. org)
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