We have a Java EE application that runs in JBoss 7.1.1, and, we must run it in VirtualMachines (such as VMWare ESXI).
The thing is, when we run our app in the VM, the performance is dropped by 50% approx.
Seems like the GC goes crazy... as far I can tell, when GC runs, it take much more longer
than normal to "end", and block the application meanwhile.
Have anyone else had a experience like that? Any tips, tunning or a light that I can follow?
Thanks in advance.
EDIT
JVM has Xmx and Xms = 1Gb
VM has 4Gb RAM
Ubuntu Server 64
oracle JVM 64
I would say that before moving your app to VM with configuration you posted it was running on 32bit system and 32bit jvm and using same jvm parameters.
Trick is that you moved to 64bit with 64bit java but still assigned same amount of heap size for your application, what has happened in reality is that you app now has half the memory available that it used to have.
Every object on 64bit jvm is twice the size of the one of 32bit jvm.
Given configuration you have I would suggest few solutions:
increase heap size to 2G
or use compressed oops
or install 32bit jvm
Given that your application does not have more than 1.3G assigned it think best performance would be achieved by installing 32bit jvm and running with -Xms1300m -Xmx1300m.
You can go even step futher and have 32bit VM with 32bit linux installation.
64bit jvm is only useful if you need more than 1.3G of heap otherwise it just adds too much overhead.
Also you can run jvm with
-verbose:gc -XX:+PrintGCDetails
that will show you what is happening with GC, this can further help you tune your jvm.
Related
A production tomcat stopped responding after 8 hours of adding more cpu and ram during runtime. There is no traceable log in catalina.out.
java process was still running in the background. There is no load on the system during that time period. No sign of Out of memory.
apache-tomcat-7.0.55
tomcat-native-1.1.31
java version "1.8.0_66"
Red Hat Enterprise Linux Server release 6.6 (Santiago)
Could it be because of the cpu and ram upgrade? Thanks.
I saw a post about it for java 6. I am not sure it is related to my issue.
http://bugs.java.com/bugdatabase/view_bug.do?bug_id=6840239
Our company IT recently went through an upgrade and I don't know what else they changed to the defaults but Excel 2013 32-bit (w/ MATLAB Compiler Runtime add in) crashes multiple times a day and it's driving me crazy.
I looked through the solutions to other similar questions but still having no luck. The exact error that I'm receiving is attached in the picture below. I've tried editing the environment variable to various amounts and checked that the free physical memory is available (has 16G total and usually half is free)
Running java -version in the command prompt returns:
java version "1.7.0_51"
Java(TM) SE Runtime Environment (build 1.7.0_51-b31)
Java HotSpot(TM) 64-Bit Server VM (build 24.51-b03, mixed mode)
The Java Control Panel Runtime Environment Settings reference javaw.exe but I changed the environment variables on both the java.exe and javaw.exe (in both Program Files and Program Files (x86).
Unable to start the JVM.
Picked up _JAVA_OPTIONS: -Xmx1024m -Xms512m
Error occurred during initialization of VM
Could not reserve enough space for budget heap
There is not enough memory to start up the Java virtual machine.
Try quitting other applications or increasing your virtual memory
It says it does not have enough space.
Change the setting for JVM Maximum Memory to 1024M
-Xmx1024m
Are there such setting for your plugin ? You might want to Google "JVM heap size settings for Excel MAtlab plugin".
Please take a look at this question as well. (Increase default heap size for windows)
Hope this helps!
When I tried to increase the JVM heap size to to 2048 Mb, it throws an exception while initializing the JVM. I have tried it on both 32-bit & 64-bit OS but was able to get the solution. Also, please tell me if installing the 64-bit JVM or JRE will solve the problem or not.
Can someone also let me know, how to find which version of JRE I'm currently running?
The memory limit is here: Java maximum memory on Windows XP
The version is java -version
Would anyone please give me ideas about forcing 64 bit jvm to run as 32-bit jvm?
I need to write a jse desktop application for bluetooth connection. For that i need to implement Bluecove jar . It has 32-bit files only. So i included -D32 under VM arguments in eclipse pulsar. But still i am getting the same error that displayed before adding the argument: bluecove_x64.dll missing. I tried with -d32, and it showed me "unrecognized option: d32".
And it seems like i should install a 32-bit jvm that would run on 64-bit os. So, can anyone please tell me what exactly should i install? Java SDK in 32-bit or Eclipse software?
Thanks in advance!
Switching modes is only possible on Solaris. A JVM is either 64bit or 32bit, except on Solaris where both run modes are available in a single JVM.
But anyway, if you don't need more than 4Gig Ram, install the 32bit JVM also on 64bit Systems, because it is 10-15% faster and needs less memory.
First, install a 32-bit JVM. (I suppose this is under Windows).
Then in Eclipse, open the Preferences panel, and go to Java -> Installed JRE's.
Click Search, tell it to search your harddisk.
Wait.
You should now see both your original 64-bit JVM and your new 32-bit JVM in the list. Put the checkmark on the 32-bit JVM instead of the 64-bit JVM. Click OK.
You should now use a 32-bit JVM in Eclipse, which should be compatible with the library you have.
As i know java programs are able to run on any Operating System.
and there are JVM's for any kind of machines.
I need a JVM that runs on my PC stand alone, and not on my OS (windows or any thing else).
I mean a JVM that acts like a boot, instead of the OS boot
i searched for all versions of JVM on "www.java.com/en/download/manual.jsp", but i did not get the suitable JVM.
the following link helped me a little but that was not enough
http://java-virtual-machine.net/other.html#jvm
my PC CPU is AMD Athlon(tm) 64X2 Dual Core Processor 5200 + 2.69 GHz
any body can help me to find the suitable jvm version ?!
Sure, have a look at JRockit Virtual Edition. As I understand it it's basically a micro kernel especially tailored for the JRockit VM.
From this page:
Java without the OS: JRockit Virtual Edition (VE)
Am I the only one that's never heard of this before? The Oracle JRockit team is looking at eliminating the OS from the stack required to run Java. This product will be called JRockit VE (not out yet)
JavaOS
Good lucking getting hold of it, though, it's nothing more than a historical curiosity.
There are two JVMs that I am aware of, which have this property:
The Fiji WM: http://www.fiji-systems.com/index.html
According to http://rtjava.blogspot.com/2009/11/new-real-time-vm-was-born-fiji-vm.html it also runs on bare metal.
The next possibility is JNode: an open source operating system where most parts are written in Java (the rest in assembly): http://www.jnode.org/
JNode is still beta, though.
No.
There was an idea of making a machine that could run a JVM as an actual machine (non virtualized), similiar to LISP machines, but that idea never took off...
You need a host OS to run a JVM.
Googling "java real machine" might give you some interesting articles.
I've found two: one from 2004, talking about how such a machine could be built and another one, talking about how JVM runs as a real machine on hardware such as mobile devices.
Still, no dice with a plain PC.