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On 2012-02-24 13:50, Jesper Wilhelmsson wrote:
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cite="mid:5B839334-95F3-47DB-801F-609C924379E9@oracle.com"
type="cite">
<div>I can have a look at it but I don't have the time to do it
today. If Monday is OK then I can take it.</div>
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<br>
Thanks, Jesper!<br>
<br>
Will also need a second review from someone with OpenJDK reviewer
status.<br>
<br>
Bengt<br>
<br>
<blockquote
cite="mid:5B839334-95F3-47DB-801F-609C924379E9@oracle.com"
type="cite">
<div>/Jesper<br>
<br>
<br>
</div>
<div><br>
24 feb 2012 kl. 13:14 skrev Bengt Rutisson <<a
moz-do-not-send="true" href="mailto:bengt.rutisson@oracle.com">bengt.rutisson@oracle.com</a>>:<br>
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Hi all,<br>
<br>
Just pinging this review request. Does anybody have some time
to look at it? It is a fairly small and straight forward
change...<br>
<br>
Thanks,<br>
Bengt<br>
<br>
-------- Original Message --------
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">Subject:
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<td>Request for review (S): 7068625 Testing 8 bytes of
card table entries at a time speeds up card-scanning</td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">Date:
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<td>Tue, 21 Feb 2012 12:03:50 +0400</td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">From:
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<td>Alexey Ragozin <a moz-do-not-send="true"
class="moz-txt-link-rfc2396E"
href="mailto:alexey.ragozin@gmail.com"><alexey.ragozin@gmail.com></a></td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">To:
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<td><a moz-do-not-send="true"
class="moz-txt-link-abbreviated"
href="mailto:hotspot-gc-dev@openjdk.java.net">hotspot-gc-dev@openjdk.java.net</a></td>
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<th align="RIGHT" nowrap="nowrap" valign="BASELINE">CC:
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<td>Bengt Rutisson <a moz-do-not-send="true"
class="moz-txt-link-rfc2396E"
href="mailto:bengt.rutisson@oracle.com"><bengt.rutisson@oracle.com></a></td>
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<br>
<br>
Hi,<br>
<br>
I would like few volunteers to review changes for <a
moz-do-not-send="true"
href="http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7068625"
target="_blank">http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7068625</a><br>
WebRev: <a moz-do-not-send="true"
href="http://cr.openjdk.java.net/%7Ebrutisso/7068625/webrev.00/"
target="_blank">http://cr.openjdk.java.net/~brutisso/7068625/webrev.00/</a><br>
<br>
Change summary<br>
For large heaps (I was focusing on 8GiB and above) it is
common to have long continuous ranges of clean cards.<br>
Patch is introducing a short path for skipping ranges of clean
cards using word aligned memory access instead of byte
aligned.<br>
<br>
Patch affects serial and CMS collectors. For CMS collector
stride size should be increase to see any performance gains (I
was using <br>
<div class="MsoNormal"
style="line-height:normal;margin-bottom:.0001pt;margin-bottom:0cm">
<span style="font-family:"Courier New"">-XX:+UnlockDiagnosticVMOptions
</span></div>
<div class="MsoNormal"
style="line-height:normal;margin-bottom:.0001pt;margin-bottom:0cm"><span
style="font-family:"Courier New"">-XX:ParGCCardsPerStrideChunk=4096)<br>
<br>
</span>For testing I was mainly using synthetic benchmark
randomly modifying hash tables in heap, thus uniformly
touching cards across heaps.<br>
Average duration of young GC pause were used as KPI.<br>
More details about testing can be found at <br>
<a moz-do-not-send="true"
href="http://blog.ragozin.info/2011/07/openjdk-patch-cutting-down-gc-pause.html">http://blog.ragozin.info/2011/07/openjdk-patch-cutting-down-gc-pause.html</a><br>
Though article is referring jdk6, my resent tests with trunk
jdk7 show no difference.<br>
I was also tested patch with real application (Oracle
Coherence storage node).<br>
With 16GiB of heap and CMS/ParNew GC, enabling patch have
shortened GC pauses roughly in 2 times.<br>
<br>
Source code of benchmark used in test are available at<br>
<a moz-do-not-send="true"
href="https://gridkit.googlecode.com/svn/branches/aragozin-sandbox/young-gc-bench">https://gridkit.googlecode.com/svn/branches/aragozin-sandbox/young-gc-bench</a><br>
Main class YoungGCPauseBenchmark<br>
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<br>
Regards,<br>
Alexey<br>
<br>
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