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From Talha Fazal <tfa...@credera.com>
Subject RE: Tomcat Performance Turning.
Date Fri, 02 Sep 2011 13:57:02 GMT
Thx Charles! We did take a thread dump and we found a lot of threads locked. Please see a short
sample below:

"http-8014-9" daemon prio=10 tid=0x0000000060965c00 nid=0x6c83 in Object.wait() [0x000000004c688000..0x000000004c688c90]
   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        at java.lang.Object.wait(Object.java:485)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.await(JIoEndpoint.java:458)
        - locked <0x00002aaae10403b0> (a org.apache.tomcat.util.net.JIoEndpoint$Worker)
        at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:484)
        at java.lang.Thread.run(Thread.java:619)

Sincerely, Talha.

-----Original Message-----
From: Caldarale, Charles R [mailto:Chuck.Caldarale@unisys.com] 
Sent: Friday, September 02, 2011 8:42 AM
To: Tomcat Users List
Subject: RE: Tomcat Performance Turning.

> From: Talha Fazal [mailto:tfazal@credera.com] 
> Subject: Tomcat Performance Turning.

> In our staging environment for load testing, when we run the load 
> test using 525 concurrent users, the app doesn't perform at all.
> The CPU usage (on Apache and Tomcat Servers) hovers between 7% to 
> 8%. The database server CPU usage is also between 4 and 5%.

Since your CPU usage is low, your threads must be waiting for something.  Take several thread
dumps and find out what.

http://wiki.apache.org/tomcat/HowTo#How_do_I_obtain_a_thread_dump_of_my_running_webapp_.3F

(I'll guess maxThreads and data base connections; a max of 30 seems a bit low for 525 concurrent
requests.)

> validationQuery="SELECT 1 FROM BB_DUAL"

Most DBs provide a very simple ping-like request capability; that would be preferable to a
select.

> -Xms512m -Xmx2048m

In a server environment, one normally sets Xms and Xmx to the same value to avoid heap thrashing.
 However, this is unrelated to your current problem.

 - Chuck


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