Survivor space fine tuning

[Pandian R <ba...@gmail.com>]

Hi,
This is the problem I am facing.

I have a tomcat 7 server running on JDK 7 - Win2008 32 bit.

I am monitoring all the memory areas. I am seeing the Survivor Space is
highly consumed almost all times. I have reduced the survivor ratio to 6.
But unfortunately no improvements. I have changed the MaxPermSize as 256
from 64 (Not sure is this a right one). Can you please suggest me a correct
option to increase the survivor space? Any help will be highly appreciated.

Here is my setting.

-Xmx1024M
-XX:SurvivorRatio=6
-XX:MaxPermSize=256

*Tomcat configration*

[image: mem06.png]

*
*
*Memory Usage on Survivor Space*


[image: java01.png]


MaxPermSize increased to 256 recently.

[image: java02.png]

Pandian R
---------------------------------------------------
*Free* software is a matter of liberty not price. You should think of
"free" as in "free speech".
Proud user of Ubuntu 11.10 - X64

RE: Survivor space fine tuning

["Caldarale, Charles R" <Ch...@unisys.com>]

> From: Pandian R [mailto:barathee@gmail.com] 
> Subject: Survivor space fine tuning

> I have a tomcat 7 server running on JDK 7 - Win2008 32 bit.

Be precise: always state the _exact_ Tomcat version, and the _exact_ JDK level.

> I am monitoring all the memory areas.

Why?  Do you have a performance problem?

> I am seeing the Survivor Space is highly consumed almost 
> all times.

That is not at all unusual; why do think it's a problem?
 
> I have reduced the survivor ratio to 6.

Why?  That more than likely just upsets the balance between eden and survivor spaces.

> But unfortunately no improvements.

You haven't indicated that there's a problem, so what are you really trying to fix?
 
> I have changed the MaxPermSize as 256 from 64

Which has nothing to do with the survivor space.  Don't change things randomly.

> Can you please suggest me a correct option to increase the 
> survivor space?

If you webapp is producing lots of objects, run a profiler on your webapp.  Tweaking internal heap settings is almost always counterproductive.  Fix your webapp, not the JVM.
 
> Tomcat configration
> Memory Usage on Survivor Space

The list strips attachments.

 - Chuck


THIS COMMUNICATION MAY CONTAIN CONFIDENTIAL AND/OR OTHERWISE PROPRIETARY MATERIAL and is thus for use only by the intended recipient. If you received this in error, please contact the sender and delete the e-mail and its attachments from all computers.

Re: Survivor space fine tuning

[Pid * <pi...@pidster.com>]

On 21 Dec 2011, at 14:23, Pandian R <ba...@gmail.com> wrote:

Hi,
This is the problem I am facing.

I have a tomcat 7 server running on JDK 7 - Win2008 32 bit.


Exactly which versions? There are 23 of Tomcat to choose from.

I am monitoring all the memory areas. I am seeing the Survivor Space is
highly consumed almost all times. I have reduced the survivor ratio to 6.


Survivor spaces fill up if objects survive a collection in Eden. How big is
that?

But unfortunately no improvements. I have changed the MaxPermSize as 256
from 64 (Not sure is this a right one).


It's not.

Can you please suggest me a correct option to increase the survivor space?


You are using the right option, but you are probably trying to change the
wrong thing.

What are you really trying to achieve?


p


Any help will be highly appreciated.

Here is my setting.

-Xmx1024M
-XX:SurvivorRatio=6
-XX:MaxPermSize=256

*Tomcat configration*

[image: mem06.png]

*
*
*Memory Usage on Survivor Space*


[image: java01.png]


MaxPermSize increased to 256 recently.

[image: java02.png]

Pandian R
---------------------------------------------------
*Free* software is a matter of liberty not price. You should think of
"free" as in "free speech".
Proud user of Ubuntu 11.10 - X64