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: Pentium3900mHz processor 256MB Ram. Operating system: win2K Tomcat 3.2.2 Thanks in advance. -srini
Re: Basic question about Apache+Tomcat Memory usage
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 [EMAIL PROTECTED] Reply-To: [EMAIL PROTECTED] To: [EMAIL PROTECTED] 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: Pentium3900mHz processor 256MB Ram. Operating system: win2K Tomcat 3.2.2 Thanks in advance. -srini
Re: Basic question about Apache+Tomcat Memory usage
ho sorry Craig i was talking about CPU usage. I know first time it translates JSP page in to Java and compiles it. But is it that much intensive to eat 80-100% of memory ?? Iam running my application on Apache+Tomcat. For many of the pages it takes 90-100% even though they are not first time visiting pages. It has Database connections. what is the problem ?? do i need to check the code or what ...? Thnaks Craig . -srini - Original Message - From: Craig R. McClanahan [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, September 07, 2001 12:10 PM Subject: Re: Basic question about Apache+Tomcat Memory usage 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 [EMAIL PROTECTED] Reply-To: [EMAIL PROTECTED] To: [EMAIL PROTECTED] 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: Pentium3900mHz processor 256MB Ram. Operating system: win2K Tomcat 3.2.2 Thanks in advance. -srini
Re: Basic question about Apache+Tomcat Memory usage
On Fri, 7 Sep 2001, srini wrote: Date: Fri, 7 Sep 2001 12:38:11 -0700 From: srini [EMAIL PROTECTED] Reply-To: [EMAIL PROTECTED] To: [EMAIL PROTECTED] Subject: Re: Basic question about Apache+Tomcat Memory usage ho sorry Craig i was talking about CPU usage. I know first time it translates JSP page in to Java and compiles it. But is it that much intensive to eat 80-100% of memory ?? If there is nothing higher priority that needs to run, don't you *want* 100% CPU usage, so the compile gets done faster? :-) Iam running my application on Apache+Tomcat. For many of the pages it takes 90-100% even though they are not first time visiting pages. It has Database connections. what is the problem ?? do i need to check the code or what ...? There's no way to give advice based on generalities here -- the only way to figure out what inside your page is eating the time is to use tools like OptimizeIt that will help you isolate the big CPU hogs. Thnaks Craig . -srini Craig - Original Message - From: Craig R. McClanahan [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, September 07, 2001 12:10 PM Subject: Re: Basic question about Apache+Tomcat Memory usage 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 [EMAIL PROTECTED] Reply-To: [EMAIL PROTECTED] To: [EMAIL PROTECTED] 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: Pentium3900mHz processor 256MB Ram. Operating system: win2K Tomcat 3.2.2 Thanks in advance. -srini
Re: Basic question about Apache+Tomcat Memory usage
srini [EMAIL PROTECTED] wrote: ho sorry Craig i was talking about CPU usage. I know first time it translates JSP page in to Java and compiles it. But is it that much intensive to eat 80-100% of memory ?? It seem to me you're confusing again CPU usage with memory... 80%/100% IS the CPU percentile activity... I am running my application on Apache+Tomcat. For many of the pages it takes 90-100% even though they are not first time visiting pages. It has Database connections. what is the problem ?? do i need to check the code or what ...? No, it means that the baby _is_ working... It's normal for a CPU to be used when you process some data, the JVM and APACHE are using all the available CPU power to deliver the response as soon as possible... If it's a peak (meaning that after you hit the page the CPU goes back to your normal load cycle) it's normal... If it stays up at 80% 100% all the time, then, there is a problem... Pier
Re: Basic question about Apache+Tomcat Memory usage
You mean the first time you access the JSP after starting Tomcat? This is because the JSP has to be compiled into a class before it can be executed. Jon - Original Message - From: srini [EMAIL PROTECTED] To: [EMAIL PROTECTED] Sent: Friday, September 07, 2001 2:14 PM 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: Pentium3900mHz processor 256MB Ram. Operating system: win2K Tomcat 3.2.2 Thanks in advance. -srini
