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From "Strecker, Mark" <mark.strec...@eds.com>
Subject RE: -Xincgc, -Xms600, -Xmx600
Date Mon, 02 Jun 2003 15:53:40 GMT
I question whether this is a memory issue. Even if you use 600MB, why does tomcat run at 100%
cpu forever??? Shouldn't the gc finish???

I have had this same problem with Tomcat for quite some time too. It seems to be an issue
with Tomcat installed as a service ... or possibly some issue with the jk connector. I run
Tomcat in my development environment and never see this behavior. The only differences between
my development and production environments are :
- the server VM is used in production ... using the client VM doesn't clear this up
- Hardware and OS ... 1 machine is identical to my development machine and the other isn't
... it occurs on NT, W2K, single and dual-cpu machines ... I'm confident this isn't a hardware
issue
- Tomcat communicates with Apache via jk ... Is there some way to investigate this?

I am using jdk1.3.1_07. I know that people upgraded to jdk1.4 and the problem persists ...
so it's probably not a JVM issue.

As far as recreating this problem, I thought that I could reliably recreate it at one time,
but I can't. I can restart the Tomcat service, not execute anything,  and within an hour the
problem is back.

I really don't have any good leads, but I have eliminated some possibilities. Any suggestions
would be greatly appreciated.

Mark

-----Original Message-----
From: Shapira, Yoav [mailto:Yoav.Shapira@mpi.com]
Sent: Monday, June 02, 2003 9:36 AM
To: Tomcat Users List
Subject: RE: -Xincgc, -Xms600, -Xmx600



Howdy,
You can enable the -verbose:gc switch and see how often GC is occurring.
Incremental GC will occur all the time pretty much.

Note that your core problem may be deeper.  Why did memory consumption
hit 600MB?  Is that expected?  If so, you should ensure the heap has
more allocated than what you expect to need.  

If this is not expected, find out what's holding on to data and modify
the relevant code so that garbage collection can reclaim this space.

Yoav Shapira
Millennium ChemInformatics


>-----Original Message-----
>From: Jason Efting [mailto:designquestions@yahoo.com]
>Sent: Sunday, June 01, 2003 9:36 AM
>To: tomcat-user@jakarta.apache.org
>Subject: -Xincgc, -Xms600, -Xmx600
>
>Hi,
>Recently my tomcat (jvm rather) 4 server started running at 100% CPU
>utilization and not service any request for long periods of time. This
must
>be due to the JVM doing garbase collection.
>
>I modified my system register appropriatly and but a few days later
(when
>memory consuption hit 600MB) tomcat started acting funny again.
>
>Here is what I did to modify my register:
>1. Stop "Apache Tomcat" service
>2. Stop "Apache" service.
>3. Modify/Add registry keys.
>4. Start "Apache Tomcat" service
>5. Start "Apache" service
>
>Please not that I did not restart the entire box.
>
>Platform:
>Windows 2000 Server SP3
>Tomcat 4
>1GB Physical RAM
>
>I cannot see any change I the servers behaviour since I modifeid the
>registry. What would you suggest I do to test my new settings and
ensure
>that incremental garbage collection is happening?
>
>Thanks
>Jason
>
>
>---------------------------------
>Do you Yahoo!?
>The New Yahoo! Search - Faster. Easier. Bingo.



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