100% cpu usage on CentOS/RHEL 6 (original) (raw)

David Holmes david.holmes at oracle.com
Tue Jul 3 04:22:53 PDT 2012

On 3/07/2012 9:07 PM, Amol Kulkarni wrote:

I dont think this is the leap-second bug bcos I can simulate it at any time using foll script. #!/bin/bash

while [ 1 ] do /usr/lib/jvm/java-1.6.0-openjdk-1.6.0.0.x8664/bin/java -version & sleep 1s done

The leap second bug seems to be occuring only near 30 Jun or 1 Jul.

That's when it activates but unless you take steps to fix it it remains in your system. The time offset used by the hrtimers remains 1 second out of sync with actual time.

I did generate a backtrace with this prb but I dont have openjdk with debug symbols - can u tell me where I can get it?

No sorry, I don't know about the OpenJDK distros available for CentOS.

Further discussion should move to hotspot-dev at openjdk.java.net cc'd.

David

On Tue, Jul 3, 2012 at 7:54 AM, David Holmes <david.holmes at oracle.com_ _<mailto:david.holmes at oracle.com>> wrote: Yes this sounds like the linux leap-second bug. Despite a lot of ignorant comments on the web this is not a bug in Java. But I would really appreciate it if someone experience this can send me a stack trace from the problematic thread(s). I think I know what is happening but need to confirm. Thanks, David Holmes

On 3/07/2012 12:02 AM, Mark Thornton wrote: On 02/07/12 14:45, Amol Kulkarni wrote: Hi, I have a java app running on CentOS 6.0. It always runs in background via cron. Sometimes this app goes into wait state while using 100% cpu. My java version is : java version "1.6.017" OpenJDK Runtime Environment (IcedTea6 1.7.4) (rhel-1.21.b17.el6-x8664) OpenJDK 64-Bit Server VM (build 14.0-b16, mixed mode) Other symptoms are : a. One thread of the process seems to be in a loop waiting for something. When traced using strace, it shows following o/p continuously : futex(0x7fb8000ac728, FUTEXWAKEPRIVATE, 1) = 0 futex(0x7fb8000ac754, _FUTEXWAITBITSETPRIVATE|FUTEXCLOCKREALTIME, Could it be related to this: https://bugzilla.kernel.org/_showbug.cgi?id=32922 <https://bugzilla.kernel.org/showbug.cgi?id=32922> Mark Thornton

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