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Date: Fri, 7 Sep 2001 12:10:33 -0700 (PDT)
From: "Craig R. McClanahan" <craigmcc@apache.org>
Sender: <craigmcc@localhost>
To: <tomcat-user@jakarta.apache.org>
Subject: Re: Basic question about Apache+Tomcat Memory usage
In-Reply-To: <005301c137d1$51d09040$6c01a8c0@ensofteklaqfgg>
Message-ID: <20010907120755.C91735-100000@localhost>
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Are you asking about CPU usage or memory usage?

For CPU, the first time you access a page (or whenever you update it),
Tomcat has to translate the page into Java and then compile it.  This is a
pretty CPU-intensive activity, but it only happens once.

For memory, there is a lot to understand about the way JVMs work -- but
basically, from the operating system point of view, the JVM will start out
at whatever you have configured as the minimum heap size, grow as it needs
to, and never give it back (although from *inside* the JVM there will be
free memory that can be reused for new Java object creation).  You can
control the overall memory usage with command line parameters -- see the
Java documentation for more info.

Craig


On Fri, 7 Sep 2001, srini wrote:

> Date: Fri, 7 Sep 2001 12:14:28 -0700
> From: srini <srinivas@ensoftek.com>
> Reply-To: tomcat-user@jakarta.apache.org
> To: tomcat-user@jakarta.apache.org
> Subject: Basic question about Apache+Tomcat Memory usage
>
> hi users,
>         i have  this basic question in mind from so many days but din't get
> an answer for it.
>          when i try to execute a simple JSP or Servlet , generally first
> time my CPU usage goes to 80-100%.I tried with default examples which comes
> with Tomcat. where as i have seen big application which don't use that much
> memory even u do some heavy jobs.
>  Why is it so ???
>
>  System configuration:
>         Pentium3    900mHz processor   256MB Ram.
>         Operating system:  win2K
>         Tomcat 3.2.2
>
> Thanks in advance.
>
> -srini
>
>