5 Replies Latest reply on May 4, 2005 8:55 PM by nwc

    idle time goes to 0 in an instant and stays that way

    nwc Newbie

      First 1 processor went to 0% idle and then 73 seconds later the 2nd processor also went to 0%, and stayed down.

      Looking at our vmstat logs, this happened yesterday at 2:06 PM, but amazingly, nobody complained about the system being unusually slow until this afternoon, at which point we restarted JBoss. Here are the facts:

      - Throughout this time, the system still responded to requests, most of the time very quickly, but sometimes not at all.

      - vmstat shows an almost constant 0% idle, the only exceptions being about 10 blibs per minute going up to 7% idle, and going to 50% idle for 2.5 seconds at exactly-60-second intervals.

      - We have a two processor machine.

      - At the time we restarted, the JVM was running about 490 threads.

      - We have maxProcessors set to 200.

      - Along with the drop to 0% idle, the context switches reported by vmstat jumped from an average of about 1000 per second to an average of about 300,000 per second.

      - This is the first time this has happened on a system that has been running under JBoss for 2.5 years, with steadily increasing traffic.

      - Last application patch was a minor one two days ago; last major patch was 2 months ago.

      - DB load and web server load during this whole time was normal.

      What could it be? An infinite loop in newly deployed code? A JBoss configuration setting that's reached a threshhold? An OS setting?

      Many thanks,