Can you describe how you open the 8 browser windows and what browser you
are using? I ask because those 8 browser windows may be coming from one
process and using at most 2 connections, hence the slower processing.
Firefox normally only has one process no matter how you open the new
windows. IE can be 8 separate processes if you launch each separately
from Explorer (ie the Start button or desktop shortcut) and not use the
new window menu option or ctrl-n.
--David
Gilbert, Antoine wrote:
Well, each process is a image rendering process.
But my point is, if I launch 8 threads directly in a JVM outside of
tomcat, it run faster and use 100% of the 8 CPU...
If I make a Servlet (or a JSP) who will start a process each time I call
it (I call it 8 times).
So, the big question is, why It's fast directly on the JVM and it's slow
on Tomcat ? Why with Tomcat It's not possible to use 100% of all the 8
CPU ? There is no data transfer between client and server, in both case
the images are rendered on the disk.
I just made this rendering test to expose the fact that I'm unable to
make my tomcat use efficiently all my CPU.
So the big question, why these 8 processes run betters than these 8
process within Tomcat ?
-----Original Message-----
From: Alan Chaney [mailto:[EMAIL PROTECTED]
Sent: 4 mai 2008 17:33
To: Tomcat Users List
Subject: Re: Tomcat problem on a multiple CPU system
Hi Antoine
The thing to remember is that this is a system which has (at least) four
main parts:
1. Tomcat
2. The operating system
3. A network connection
4. Your application
(and potentially)
5. A database (but you didn't mention that)
Here are some questions.
1. How do you make the connection to the servlet. Does the browser run
on the same machine as the application?
2. Does you application create network traffic? If so, how many bytes
are transferred to the browser? Each servlet thread will have to wait
until the application has transferred all the data out.
3. What kind of disk activity does your application generate? Is it
different when the app is running from the servlet?
Probably somewhere your servlet threads are sleeping waiting for a
resource. You could do a thread dump to see what is happening (I don't
use Windows so I can't remember how you do that with the Win setup)
In the end, you'll need to profile the system to work out where the
bottlenecks are. You'll need to use network analysers and probably Java
profilers to track down what's happening such as when packets are
received, when the replies are generated and maybe profile what your
app. is doing.
HTH
Alan Chaney
Gilbert, Antoine wrote:
Hi
I have a 2x quad core (8 cpu units) server.
If I start a java program and this one is launching (at the same time)
8
thread doing some CPU intensive jobs, all the CPU are used at 100%,
and
that's what I'm expecting..
But, if I am using tomcat, and I call a servlet 8 times to process
these
8 jobs, it take longer to execute these same 8 jobs and all the CPU
are
not used at 100%, it's more like 30%...
Any idea about this problem or behavior ? I'm using Tomcat 5.5.17,
windows, JDK 1.6
Antoine
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