Re: Infinite loop?

["Frances Stewart" <francess@xxxxxxxxxx>]

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


DV-Beratung Dieter Bender
Wetzlarerstr. 25
35435 Wettenberg
Tel. +49 641 9805855
Fax +49 641 9805856
www.bender-dv.de
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