topic java_q4p on itanium-based server in Operating System - HP-UX

java_q4p on itanium-based server

hnt — Sun, 24 Sep 2006 23:01:16 GMT

Hi,

We are running java application (32bit) on rx2600 machine with java 1.4.2_07 installed.

java version "1.4.2.07"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2.07-050121-15:53)
Java HotSpot(TM) Server VM (build 1.4.2 1.4.2.07-050121-21:06-IA64N IA64, mixed mode)

recently, We upgraded memory from 4G to 12G and changing max heap size of the java process to 1536M.

According to document, if heap size is between 1500M-3.5G, executable java is "java_q4p". However,
doing grepping for the java shows that it's running as usual "java" instead of "java_q4p".

ps -axef | grep java shows
root 6198 6195 0 11:31:26 ? 1:03 /opt/java1.4/bin/IA64N/java -Xmn256m -Xmx1536m
-XdoCloseWithReadPending -XX:+UseGetTimeOfDay....

and ps -e | grep 6198 shows
6198 ? 1:03 java

Someone please advice why the executable java is not "java_q4p" in my case.

reference : http://www.hp.com/products1/unix/java/infolibrary/prog_guide/expanding_memory.html

Thanks in advance.

Re: java_q4p on itanium-based server

Steven E. Protter — Sun, 24 Sep 2006 23:26:33 GMT

Shalom,

Is the application still working?

I think this may simply be inadequate documentation. The newer versions of java should be able to adjust for large memory size without a different executable.

http://www.hp.com/go/java

SEP

Re: java_q4p on itanium-based server

RAC_1 — Sun, 24 Sep 2006 23:50:15 GMT

With chatr, you can set java to use fourth quadrant. man chatr. (I am not sure that applies here though)

Re: java_q4p on itanium-based server

hnt — Mon, 25 Sep 2006 02:05:30 GMT

Hi Steven,

Do you have any idea in which version that java is able to adjust larger heap without different executable??

Regards,
hnt

Re: java_q4p on itanium-based server

hnt — Mon, 25 Sep 2006 04:33:07 GMT

Hi,

I just found out that only if max heap size is configured as 1700m, executable java is "java_q4p". Otherwise, for heap size less than 1700m, "java" is used instead.

I have no idea of the difference between what I have done and the release note.

Re: java_q4p on itanium-based server

Peyman Javaheri — Tue, 26 Sep 2006 11:51:40 GMT

Hi,

You are right about the java_q4p. You don't have to change/chatr your java In fact I do not recommend that. Either use java_q4p or let java to choose that for you.

I assume that you know that, you are stuck with 3.8GB max heap as long as you stay in 32-bit. The only way out of this will be to go to 64-bit.

Check the website mentioned by our friends above (hp.com/go/java). You will find tools like HPJtune and ways to use Glance to provide you the details you need. If you have Glance (or Tial version), In Glance you will have to look for your Other VSS for your selected process. That gives you your total heap usage.

HP-UX is limited in that aspect. You can also get the VerboseGC outputs to a gc file and open it using HPJtune. That also provides you insight about your jvm heap per process.

regards,
peyman;