Java spikes CPU to 100%

SUSE Product Topics SLES Configure-Administer
1

Hi -

I’m new to configuring SLES. I have SP2:
[INDENT]SUSE Linux Enterprise Server 11 (x86_64)
VERSION = 11
PATCHLEVEL = 2
[/INDENT]

It’s running on a VMWare Fusion 3.1.4 (OSX 10.7). The VM is allocated 4 cores and 6GB RAM. It’s running IBM Java.

[INDENT]java version “1.6.0”
Java™ SE Runtime Environment (build pxa6460sr7-20091215_02(SR7))
IBM J9 VM (build 2.4, JRE 1.6.0 IBM J9 2.4 Linux amd64-64 jvmxa6460sr7-20091214_49398 (JIT enabled, AOT enabled)
J9VM - 20091214_049398
JIT - r9_20091123_13891
GC - 20091111_AA)
JCL - 20091202_01[/INDENT]

When I run Java programs as a user, the CPU spikes to 100% and stays there. In System Monitor, the task is Sleeping in futex_wait_queue_me. When I run Java programs as root, the CPU is normal and the task is in the same state.

Clearly this is a permissions problem but I can’t figure out where. Any ideas?

Thanks in advance,
Bob

2

Hi
This should give you some more clues on what to run for more
information
http://stackoverflow.com/questions/9801256/app-hangs-on-futex-wait-queue-me-every-a-couple-of-minutes
http://randomlyrr.blogspot.it/2012/03/java-tuning-in-nutshell-part-1.html

–
Cheers Malcolm °¿° (Linux Counter #276890)
SUSE Linux Enterprise Desktop 11 (x86_64) Kernel 3.0.31-0.9-default
up 15:13, 2 users, load average: 0.93, 0.95, 0.98
GPU GeForce 8600 GTS Silent - Driver Version: 302.11

3

Thanks Malcolm. I tried many of those but it doesn’t seem to affect the behavior at all.

4

Hi
Can you provide some more information (Requested by my SUSE contacts);
1 - Is the java application in the guest?
2 - Does it occur with other java applications?
3 - Have you tried the other java implementations (OpenJDK, Sun)?
4 - Tried with any other virtualization setups, kvm, Xen etc
5 - What is the java application, is it possible to get it for testing?
6 - Is the cpu utilization on the host high as well?

–
Cheers Malcolm °¿° (Linux Counter #276890)
SUSE Linux Enterprise Desktop 11 (x86_64) Kernel 3.0.31-0.9-default
up 19:27, 2 users, load average: 1.21, 1.55, 1.85
GPU GeForce 8600 GTS Silent - Driver Version: 302.11

5

[QUOTE=malcolmlewis;5201]Hi
Can you provide some more information (Requested by my SUSE contacts);
1 - Is the java application in the guest?
2 - Does it occur with other java applications?
3 - Have you tried the other java implementations (OpenJDK, Sun)?
4 - Tried with any other virtualization setups, kvm, Xen etc
5 - What is the java application, is it possible to get it for testing?
6 - Is the cpu utilization on the host high as well?
[/QUOTE]

  1. Yes.
  2. Yes (Hadoop and Cognos), each on it’s own VM of SLES SP2, same version of Java.
  3. Nope, I guess I can try that.
  4. Nope, will definitely try that.
  5. Hadoop and Cognos
  6. Yes. The fans start up too.
6

Did you try to look inside the JVM with jconsole?
If you didn’t, try it ( http://docs.oracle.com/javase/1.5.0/docs/guide/management/jconsole.html , http://www.oracle.com/technetwork/java/gc-tuning-5-138395.html are the two docs I dig out of my bookmarks every time I need to refresh my memories with java - but chances are that you have more expertise in this area than me… ) I
'm quite sure that the number of Garbage Collections will be huge, because of the VM’s trashing… if not, you’ll still be able to see what happens.

7

[QUOTE=enovaklbank;5235]Did you try to look inside the JVM with jconsole?
If you didn’t, try it ( http://docs.oracle.com/javase/1.5.0/docs/guide/management/jconsole.html , http://www.oracle.com/technetwork/java/gc-tuning-5-138395.html are the two docs I dig out of my bookmarks every time I need to refresh my memories with java - but chances are that you have more expertise in this area than me… ) I
'm quite sure that the number of Garbage Collections will be huge, because of the VM’s trashing… if not, you’ll still be able to see what happens.[/QUOTE]

Well after days of struggles, I finally found a solution. As suspeted, it was in fact a permissions problem. I found a file in the /tmp folder called .com_ibm_tools that was owned by root. When I chown’d that to my user, the server stopped thrashing.