Below thread is taken from the gmane archive of jetty support mail list
(explains the proc issues)
Performance is still a concern.
I'm running appache providing ssl and php app support and proxying through
to jetty for all lenya content.
Any performace tips greatly appreciated
Lee C
From: Heiner Westphal <susp48 <at> verit.de>
Subject: Re: Lots of processes running under Linux
Newsgroups: gmane.comp.java.jetty.support
Date: 2005-04-04 07:50:03 GMT (13 weeks, 5 days, 4 hours and 42 minutes ago)
Eric,
on 2.4.x linux kernels ps shows a line for each thread.
This changed on 2.6.x kernels.
And, as Chris stated, the memory infos are just duplicated
for each thread.
If you sum it up it makes you nervous.
But since jetty runs in one JVM and one JVM cannot run in
more than one process, what you see is the list of threads,
not processes.
AFAIK there is no mechanism in jetty to fork another JVM
(other than doing it yourself using Run or System or something).
HTH,
Heiner
Eric Rizzo wrote:
On Apr 3, 2005 4:56 AM, Chris Haynes <chris <at> harvington.org.uk> wrote:
Greg or Jan can give you the definitive answer on the number of threads
needed,
but I don't think it should be as high as you are seeing.
I did some tests a few months ago and thought I was using 1 for the stop
listener and exactly the right number accounted for by my declared
listeners.
Are you starting Jetty with just one service; just one .xml file in the
start
line?
On the memory issue - Don't Panic!
I run on SuSe Linux, but I expect Debian is the same in this respect...
You have only one JVM, and so one set of memory. The threads all take
their
memory from within this one JVM allocation. The 'ps' listing can't see
inside
the JVM to see how much memory each thread is using, so it just lists the
size
of the (one) JVM against all of its threads!
Thanks for taking the time to reply. However, I am not talking about
threads - multiple thread don't bother me - what I'm seeing (or think
I'm seeing, at least) is a lot of individal processes. I first saw it
by doing the simple "java -jar start.jar" from the Jetty install
directory. I only tried tweking down the listener thread pool as a
"grasping at straws" attempt to find the cause of so many individual
processes.
I'm no Linux guru, but neither am I a *nix newbie, and I don't think
ps and top should be listing a separate processes for every thread
(even if the Jetty config I was using was creating 20 threads, which
I'm pretty sure it is not configured to do).
Eric
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