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:[email protected]]
Sent: Friday, September 02, 2011 8:42 AM
To: Tomcat Users List
Subject: RE: Tomcat Performance Turning.
> From: Talha Fazal [mailto:[email protected]]
> 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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