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From "Ralph Einfeldt" <ralph.einfe...@uptime-isc.de>
Subject AW: Tomcat Apache Linux processes
Date Fri, 09 Nov 2001 09:36:16 GMT
The VM needs around 5 threads to run one program.
The exact number of threads depends on the vendor 
and the version of the jdk. 
With IBM's JDK 1.3 and JServ i see following threads
for new startet inactive site:
  - Reference Handler
  - Finalizer
  - Signal dispatcher
  - main
  - thread-0
  - thread-1

The additional number of threads depend on several
implementation and configuration details of the 
servlet container and the vm.

For example if the VM implements a thread pool
to serve the native threads, the number of threads
you see with ps doesn't say much about the threads 
that are currently used by the servlet engine.

The servlet engine it self can also implement
a threadpool to serve the java threads.

Try a little experiment:
  - make shure that stderr and stdout are redirected to a file
  - Send kill -QUIT to one of the threads
  - Look in the file to see what the threads where doing
    (Sun + IBM JDK will dump a stacktrace for all threads)

> -----Ursprüngliche Nachricht-----
> Von: Christophe Geraud [mailto:geraud@cls.fr]
> Gesendet: Freitag, 9. November 2001 09:36
> An: Tomcat Users List
> Betreff: Re: Tomcat Apache Linux processes
> 
> 
> Hello,
> 
> Ok, 35 process is just in fact 35 thread (in 1 Linux process).
> But ...
> Where comes from the "35" ?
> Is it needed to manage the process number ?
> 
> For my application, maximum 20 users at a time, I suppose 5 
> thread are enough.
> is'n it ?
> 
> 
> David Hamilton a écrit :
> 
> > I believe (might just be vicious rumour, however!) that the 
> IBM VM uses its
> > own threading library, and does not suffer a number of the 
> issues that the
> > Sun one has in this respect.
> >
> > Cheers
> >     david
> >
> > ----- Original Message -----
> > From: "David Smith" <dns4@cornell.edu>
> > To: "Tomcat Users List" <tomcat-user@jakarta.apache.org>
> > Sent: Thursday, November 08, 2001 5:04 PM
> > Subject: Re: Tomcat Apache Linux processes
> >
> > If you're looking at it with ps, memory for each thread 
> doesn't really
> > increase.  More like memory for the entire tomcat process 
> increases and it's
> > reflected in the ps listing.  Notice that the memory of 
> each thread is
> > exactly the same.  All things being equal and resources 
> properly returned to
> > the JVM, memory consumption should stabilize after it services some
> > requests.
> >
> > I agree with others that the threading model in Linux needs 
> some serious
> > help.
> >
> > --David Smith
> >
> > On Thursday 08 November 2001 11:43 am, you wrote:
> > > Ok !
> > > But how to manage this number of thread ?
> > > How to set it ?
> > >
> > > Some strange thing :
> > > I send a request to the servlet ... and the size of the 
> memory of each
> > > thread increase !!!
> > > Why ?
> > >
> > > Thanks for help.
> > >
> > > Christophe
> > >
> > > Martin van den Bemt a écrit :
> > > > One of them is the process and the rest of the 34 are 
> threads, which
> > > > under linux show up in the process list.
> > > >
> > > > Mvgr,
> > > > Martin
> > > >
> 
> 
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