Re: Infinite loop?

[Dieter.Bender@xxxxxxxxxxx (Dieter Bender)]

Frances,

I've forgotten to mention:
I've used DMPJVM for the dump

Dieter

On Monday 23 December 2002 04:15, you wrote:
> Well, that could be irritating.
>
> When you dump the process are you using SST (STRSST, and subsequent
> options)? Also doing wrkactjob, finding job, option 5 and then option 20
> and then option 10 on thread running shows nothing (is that what you were
> saying below with "impossible to show the thread info...")?
>
> Is there other activity on the system - perhaps activity which runs at a
> better priority that WAS (WAS runs at priority 25 by default) at the time
> or just prior to when the CPU usage spikes? Maybe large database activity
> form the app server itself?
>
> Anything in the WAS log files at the time of CPU usage spike?
>
> Have you noticed if the number of threads decreases to 2 (one, the
> main/first thread, waiting and a second thread running), when you do the
> endjob?
>
> Are you up to date on all  other PTFs (3.5.6 is of course the latest level
> of WAS)?
>
> Frances Stewart
> WebSphere Application Server for iSeries 400
> IBM Rochester
>
>
>
>
>                       Dieter.Bender@t-o
>                       nline.de (Dieter         To:
> java400-l@midrange.com Bender)                  cc:
>                       Sent by:                 Subject:  Re: Infinite loop?
>                       java400-l-admin@m
>                       idrange.com
>
>
>                       12/22/2002 02:52
>                       PM
>                       Please respond to
>                       java400-l
>
>
>
>
>
> Frances,
>
> On Sunday 22 December 2002 15:29, you wrote:
> > Ito might be that the garbage collector has kicked in for some reason
>
> (such
>
> > as alot of stuff to collect) and is trying to cleanup. I have seen sone
> > case where the job appeared like it would not end, but in actuality it
>
> took
>
> > to 14 hours, because the collector was returning heap to the system (that
> > is the simplified form of what was happening).
> >
> > A process dump of all the threads (or the single thread) when the job is
> > consuming the CPU would show whether it was the garbage collector or not,
> > and also would show the stack for the thread in question.  Have done a
>
> the dump fails with timeout and it's impossible to show the thread
> information with the same problem.
>
> > WRKSYSSTS to see if storage is being returned (i.e. percent used is going
> > down) or if there is an inordinate amount of paging etc. going on in the
> > storage pool in which WAS runs?
>
> no paging, no consumption of storage.
>
> > What I would recommend ideally is that you talk to IBM Support about the
> > problem and get things setup so that when the problem occurs (hopefully
> > during normal working hours), IBM Support can get on the system and debug
> > the problem.
>
> And here starts my problem, we are in germany and ibm support tells that
> there must be a problem with the application and WAS performs fine. And
> they
> are telling we should write a little program wich makes the problem
> reproducable.
>
> Dieter
>
> > Frances Stewart
> > WebSphere Application Server for iSeries 400
> > IBM Rochester
> >
> >
> >
> >
> >                       Dieter.Bender@t-o
> >                       nline.de (Dieter         To:
> > java400-l@midrange.com Bender)                  cc:
> >                       Sent by:                 Subject:  Infinite loop?
> >                       java400-l-admin@m
> >                       idrange.com
> >
> >
> >                       12/22/2002 04:39
> >                       AM
> >                       Please respond to
> >                       java400-l
> >
> >
> >
> >
> >
> > Hi,
> >
> > we use WebSphere 3.5.6 running on as400 V5R1;
> > from time to time CPU usage reaches near 100% all used by one thread of
>
> the
>
> > application server. Nobody is working with the application and only
> > PWRDWNSYS
> > *immed brings down WebSphere. It's impossible to end the server from the
> > WepSphere console, or to stop it in another way. Neither endjob, normal
>
> or
>
> > abnormal, nor endsbs kills WebsFear.
> > It looks like an infinite loop, maybe in the JIT compile. CRTJVAPGM to
> > clearify this is a little bit complicated, beacause we use JSPs and it is
> > running hours to days.
> > The problem doesn't occur running WebSphere on another box (NT).
> >
> > any ideas?

--
mfG

Dieter Bender


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