Re: [Wrapper-user] jvm hung and high CPU usage with wrapper

[Leif M. <lei...@ta...>]

Hello,
My first guess here is a configuration problem of some sort.

1) When you enabled the wrapper.debug output, there should be a Java
command line displayed at the top of the log.    Could you please
verify that the Wrapper is launching the same JVM version when running
as a service, as a console, and when you run without the Wrapper?   A
fairly common problem is that users run the wrong JVM version because
the Wrapper locates Java on the system path by default.  The PATH is
not always defined the same for various users.
As you are only seeing some problems with the Wrapper, I think this
might be happening with you.

2) 3.2.3 is fairly old, so I think I am aware of most problems in that
version.  There are no problems that I am aware of that would be
isolated to single core machines and none that cause a large CPU
usage.  There have been some synchronization problems over the years
that showed up on multiple CPU systems, but not the other way around.

3) Another user had a problem s couple years ago where their
application was eating lots of CPU when run under the Wrapper.  It
turned out to be a problem in the user's code.   They had code like
this:

while (true) {
    try {
        doSomething();
        Thread.sleep(60000);
    } catch ( Throwable t ) {
        // ignore
    }
}

The doSomething code was throwing an exception due to a path reference
error and the sleep was being skipped.
Are you able to tell which thread in your application is eating all of the CPU?

Cheers,
Leif

On Thu, Aug 20, 2009 at 12:40 AM, hhale21<hh...@ya...> wrote:
>
> Hello,
>
> I am using JSW 3.2.3.  We are experiencing some odd behaviour of our servers
> on single CPU/core Windows XP/SP3 (32bit) computers.  I am looking for ways
> to try and troubleshoot this problem.
>
> There are 3 different servers running as windows services using the
> wrapper.exe.
> On a regular basis 1 or more of these servers is getting jvm hung messages
> and are being started.
> This seems only to occur on single core/CPU computers.  Have not observed
> this on multi core CPUs.  I have wrapper.debug=true in the conf files. I
> don't seen anything in the log files other that logging for the application
> stops completly for 30 secs (default wrapper ping value) before the jvm is
> restarted.
>
> I tried starting one of the servers using the wrapper.exe as regular process
> (as opposed to a service). The hang does not occur however one of the
> threads in the application is using almost 100% of the CPU constantly. I am
> using Process Explorer inspect the process.   JVM has not occurred when not
> run as service.
>
> When I run the server without the wrapper.exe,  I don't have the thread that
> uses 100% of the CPU and so far the server has run with out any issues.
>
> Just looking for some feedback on how to troubleshoot this problem.
>
> Thanks
> --