Discussions

Performance and scalability: High CPU usage by OC4J on starup

  1. High CPU usage by OC4J on starup (2 messages)

    Environemnt: OC4J 9.0.3, JDK 1.4.1

    Problem: On startup, our web app (JSP/servlets) uses a high % of CPU (about 45%) and stays there. All that has happened is that the application has been loaded in memory. There are no background processes running on startup.
    When the first web activity is recorded, the CPU % is reduced to a low number (5-10%). This number is even more reduced when no subsequent activity is recorded.

    Question: I would like to bring the high initial CPU % to a low number without having to perform a web activity. I am wondering why an initial web activity (such as a click on a JSP button) helps JVM reduce its CPU usage. I have tried to force the application to not load on startup by setting the auto-start of server.xml to false as well as and load-on-startup=false in web-site.xml, but have not been successful.

    ANY IDEAS will be appreciated.
  2. Using a tool such as JProbe or OptimizeIt to profile that activity might be provide the information you need. There's a 7 day trial for JProbe. I bet you could figure the issue out in an afternoon with a tool like one of these.
  3. Thanks, I will give it a shot.