<div dir="ltr">Hi.<br><br>I actually already got the stack trace via GDB, here is the link again:<br><a href="http://pastie.org/996680" target="_blank">http://pastie.org/996680</a><br><br>The main problem with it that it's not clear which native library the code is stuck in.<br>
Can any of the service agents get me more info, like for example the loaded native libraries?<br><br>Thanks.<br><br><div class="gmail_quote">On Tue, Jun 8, 2010 at 9:46 PM, Paul Hohensee <span dir="ltr"><<a href="mailto:paul.hohensee@oracle.com">paul.hohensee@oracle.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">The first thing we suspect when we see a hang or memory stomp (your<br>
hang might be caused by a memory stomp) is native code running as part<br>
of the application. I'd try running your app under a debugger or attach<br>
to it with a debugger or the serviceability agent to get stack traces. See<br>
<br>
<a href="http://openjdk.java.net/groups/serviceability/svcjdk.html" target="_blank">http://openjdk.java.net/groups/serviceability/svcjdk.html</a><br>
<br>
for serviceability tools in general.<br>
<br>
The switches you mention are<br>
<br>
-XX:-ReduceInitialCardMarks<br>
<br>
which works around a gc bug. In some cases there will be a slight gc performance loss<br>
using this switch. It may fix your problem<br>
<br>
-XX:-UseBiasedLocking<br>
<br>
will disable the fastest path uncontended locking algorithm. You may or may not see<br>
a performance hit by doing so. Biased locking has been pretty reliable for quite awhile,<br>
so it's not too likely that turning it off will fix your problem.<br><font color="#888888">
<br>
Paul</font><div><div></div><div class="h5"><br>
<br>
On 6/8/10 2:35 PM, Stas Oskin wrote:<br>
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
Hi.<br>
<br>
I encountered the hang in latest jdk1.6.0_20 version.<br>
<br>
I tried to get the threads dump, but both jstack and kill -3 didn't produce any results.<br>
Below is the GDB dump:<br>
<a href="http://pastie.org/996680" target="_blank">http://pastie.org/996680</a><br>
<br>
Earlier in this thread I receive that possible cause is the dlsym function in libdl library. I googled a bit for similar issues, and found only the following potentially similar case:<br>
<a href="http://www-01.ibm.com/support/docview.wss?uid=isg1IZ07615" target="_blank">http://www-01.ibm.com/support/docview.wss?uid=isg1IZ07615</a><br>
<br>
I also received advices to:<br>
<br>
* ReduceInitialCardMarks<br>
or/and<br>
* UseBiasedLocking<br>
<br>
Which one of them may solve the issue, and what the possible results would be?<br>
<br>
Thanks in advance.<br>
</blockquote>
</div></div></blockquote></div><br></div>