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Hi Uwe,<br>
<br>
The default mark stack size for 32 bit is 32K entries. So try
-XX:MarkStackSize=32K. This might not overflow because the local
marking task queues are larger in the 64 bit JVM so there will be less
pressure on the global mark stack. Unfortunately the task queue size is
a constant (actually a template constant either 16K for 32 bit and 128K
for 64 bit). You might have to go lower.<br>
<br>
JohnC<br>
<br>
On 03/06/13 11:31, Uwe Schindler wrote:
<blockquote cite="mid:007801ce1aa1$43cedb90$cb6c92b0$@apache.org"
type="cite">
<pre wrap="">Hi,
</pre>
<blockquote type="cite">
<blockquote type="cite">
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">Uwe:
Thanks for bringing this up and my apologies for not replying sooner.
I will have a fix fairly soon. If I'm correct about it being caused
by overflowing the marking stack you can work around the issue by
increasing the MarkStackSize.you could try increasing it to 2M or
4M entries (which is the current max size).
</pre>
</blockquote>
<pre wrap="">Is there a setting on the command line to raise this size? This
would be
</pre>
</blockquote>
<pre wrap="">great to check out if one can also do the opposite (lower the size on
64 bit JVM to make the 64 bit one also hang). Unfortunately as a Java
programmer I am not so familiar with building the JVM on Ubuntu
machines (including the needed IcedTea), so it's hard to me to try
this out - I would not even know how to start doing this or finally
how to get something like a standard JDK directory so you could use it as
</pre>
</blockquote>
<pre wrap="">JAVA_HOME.
</pre>
<blockquote type="cite">
<pre wrap="">Use: -XX:MarkStackSize=4M to increase the marking stack size in a 32 bit
</pre>
</blockquote>
<pre wrap="">run.
I will give it a quick try!
</pre>
</blockquote>
<pre wrap=""><!---->
4M was too much for a 32bit JVM (it complained about it), but 2M was fine. With that setting the tests went through as they should (in 22 secs on this server). With the default setting it stalled endless.
To test the inverse (make 64 bit hang): What's the default stack size of 32 bit JVMs, so I can set it on 64 bit to make it hang?
Uwe
</pre>
<blockquote type="cite">
<pre wrap="">-----
Uwe Schindler
<a class="moz-txt-link-abbreviated" href="mailto:uschindler@apache.org">uschindler@apache.org</a>
Apache Lucene PMC Member / Committer
Bremen, Germany
<a class="moz-txt-link-freetext" href="http://lucene.apache.org/">http://lucene.apache.org/</a>
</pre>
<blockquote type="cite">
<pre wrap="">-----Original Message-----
From: John Cuthbertson [<a class="moz-txt-link-freetext" href="mailto:john.cuthbertson@oracle.com">mailto:john.cuthbertson@oracle.com</a>]
Sent: Wednesday, March 06, 2013 7:56 PM
To: Uwe Schindler
Cc: 'Thomas Schatzl'; <a class="moz-txt-link-abbreviated" href="mailto:hotspot-gc-dev@openjdk.java.net">hotspot-gc-dev@openjdk.java.net</a>; 'David Holmes';
'Dawid Weiss'; <a class="moz-txt-link-abbreviated" href="mailto:hotspot-dev@openjdk.java.net">hotspot-dev@openjdk.java.net</a>
Subject: Re: JVM hanging when using G1GC on JDK8 b78 or b79 (Linux 32
</pre>
</blockquote>
<pre wrap="">bit)
</pre>
<blockquote type="cite">
<pre wrap="">Hi Uwe,
You must have been reading my mind. See inline....
On 3/6/2013 10:50 AM, Uwe Schindler wrote:
</pre>
<blockquote type="cite">
<pre wrap="">Hi John,
Thanks for the response and the analysis, very informative!
</pre>
<blockquote type="cite">
<pre wrap="">Uwe:
Thanks for bringing this up and my apologies for not replying sooner.
I will have a fix fairly soon. If I'm correct about it being caused
by overflowing the marking stack you can work around the issue by
increasing the MarkStackSize.you could try increasing it to 2M or 4M
entries (which is the current max size).
</pre>
</blockquote>
<pre wrap="">Is there a setting on the command line to raise this size? This would be
</pre>
</blockquote>
<pre wrap="">great to check out if one can also do the opposite (lower the size on 64 bit
JVM to make the 64 bit one also hang). Unfortunately as a Java
</pre>
</blockquote>
<pre wrap="">programmer I
</pre>
<blockquote type="cite">
<pre wrap="">am not so familiar with building the JVM on Ubuntu machines (including the
needed IcedTea), so it's hard to me to try this out - I would not even know
how to start doing this or finally how to get something like a standard JDK
directory so you could use it as JAVA_HOME.
Use: -XX:MarkStackSize=4M to increase the marking stack size in a 32 bit
</pre>
</blockquote>
<pre wrap="">run.
</pre>
<blockquote type="cite">
<blockquote type="cite">
<pre wrap="">If you need a verification that your patch is working, it would be good to
</pre>
</blockquote>
</blockquote>
<pre wrap="">get
</pre>
<blockquote type="cite">
<pre wrap="">a i586 Linux tgz file with a binary, so I can do a quick check on the Jenkins
server that found the bug. Otherwise we would need to wait until a new
build appears on jdk8.java.net (including the fix + other fixes in
</pre>
</blockquote>
<pre wrap="">javadoc/javac
</pre>
<blockquote type="cite">
<pre wrap="">tool and the class library that we reported earlier).
</pre>
<blockquote type="cite">
<pre wrap="">I could also assist in setting up a Lucene build directory (as
reported on the first email), to reproduce the problem with the Lucene
source code (which is very easy). As said before, I have no isolated
test case :(
</pre>
</blockquote>
<pre wrap="">I just sent you email. I downloaded a zip file that contains all the jar files. I
don't have ant on my system so ideally I'm looking for a java command line
</pre>
</blockquote>
<pre wrap="">to
</pre>
<blockquote type="cite">
<pre wrap="">tickle the crash. Can you help?
Thanks,
JohnC
</pre>
</blockquote>
</blockquote>
<pre wrap=""><!---->
</pre>
</blockquote>
<br>
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