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From "Duan, Nick" <ND...@mcdonaldbradley.com>
Subject RE: heap size problems (speed) [2]
Date Mon, 28 Nov 2005 17:30:58 GMT
Were you using the right JVM?  There were two JDK download for LINUX on
Sun's web site.

The main problem may be your AMD Duron processor which has a very small
cache size (I believe it's about 512K).  Once the processor cache
reaches its limit, increasing the JVM heap size won't be very effective.

ND


-----Original Message-----
From: Cristian [mailto:cs@nightwish.eu.org] 
Sent: Monday, November 28, 2005 6:19 AM
To: Tomcat Users List
Subject: heap size problems (speed) [2]

Although it may seem obvious what is the problem, I forgot to ask the
question so I'm doing it now:

What could be the problem in the below described situation ?

I would appreciate if you point some docs that I should read to solve
the issue.

Thanks again,
Cristian

Original message follows:

Hello,

 I have an instance of tomcat with APR support which is set to allocate
more heap memory than default (by passing -Xmx512M option to JAVA_OPTS
in catalina.sh).

 Under this instance runs a test application which gets data from a
database and makes a cache with the fetched data (around 350M). When the
app is accessed it is supposed to return data from the cache (which is
in a form of a hashmap) faster than getting it from the database.

After the caching is done the application responds extremely slow and
above this many images aren't loaded or they are loaded partially in the
browser (I haven't checked to see if the images are the only ones that
are not loaded).

The system:
= Kernel: Linux server2 2.6.14-1.1637_FC4 #1 Wed Nov 9 18:19:37 EST 2005
i686 athlon i386 GNU/Linux

= Processor: AMD Duron 1000MHz

= Tomcat: 5.5.12 with APR 1.2.2 (compiled apart from apr-0.9.6-3.1 which
is in the distrib)

= RAM: 1G


The system has all updates.

I am not the one who wants the test so don't blame me for any stupidity
that you might found in this scenario :).

I get the same results on a different machine which is much faster and
has twice as much memory than this one from the test.

Thanks,
Cristian


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