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From "Allistair Crossley" <>
Subject RE: Tomcat performance issue?
Date Mon, 12 Apr 2004 22:16:21 GMT
This evening I did the same with JProbe under 360 requests as you describe and this led to
me gaining a 38% speedup.
The main bottleneck I found was some very simple tags I have were calling out.flush() at the
end. Thiw was consuming 14 seconds of time to flush 1 string from the tag. The tag is called
many times within our JSPs because it calls the current skin label.
By simply removing the flush call the tag call method time across the load test went down
to 2s. Not bad hey. There were other areas which I solved with application scope caching and
a bean pool for a 3rd party bean that takes ages to initialise a connection.
I am getting there slowly but surely but Yoav I think was right all along and it is the code
and you have to profile it and examine those call graphs!!!

	-----Original Message----- 
	From: Peter Lin [] 
	Sent: Mon 12/04/2004 19:53 
	To: Tomcat Users List 
	Subject: Re: Tomcat performance issue?

	luckily I have a license of Borland OptimizeIt.
	What I do is I start tomcat using OptimizeIt. Then I create a test plan in JMeter. Once tomcat
is running, I warm it up by sending it a couple hundred requests to make sure all the pages
are compiled.
	before the test starts, use OptimizeIt to garbage collect. Once that is done, I start the
test and look at the number of threads and size of the heap. If there's a memory leak, either
the thread count will increase, or the heap will grow rapidly. Once I see either one, I then
switch to the call graph to get a better picture of which methods are getting called. Usually,
that is enough to point towards a culprit.
	repeat, and rinse as many times as needed until you've squashed all bugs and leaks.
	peter lin
	Matt Woodings <> wrote:
	I just read your post this morning (I am lurking today as I have a few
	issues of my own to clear up :-) ) and I think that is some really good
	advice you gave. I do have a question though.
	Once you have noticed you have a memory leak, how do you go about locating
	Do you Yahoo!?
	Yahoo! Tax Center - File online by April 15th 

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