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Tony,<br>
<br>
I'm still studying the patch but would you consider a more explicit<br>
flag to turn this on and off? What you have is very reasonable but<br>
if the performance team sees some regression, it would be easier<br>
for them to turn the feature on or off rather than go look for the
value<br>
of <span class="new">ParGCCardsPerStrideChunk</span> that is the
default and then put that<br>
on the command line. Same would be true for a customer who has<br>
an application operating in one of the corners where the performance<br>
is worse.<br>
<br>
Jon<br>
<br>
<div class="moz-cite-prefix">On 6/17/2015 3:30 PM, Tony Printezis
wrote:<br>
</div>
<blockquote
cite="mid:etPan.5581f51b.699a1ea0.1215a@tw-mbp-tprintezis"
type="cite">
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<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Hi all,</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br>
</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;">A small patch
for your consideration:</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br>
</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><a
moz-do-not-send="true"
href="http://cr.openjdk.java.net/%7Etonyp/8086056/webrev.0/">http://cr.openjdk.java.net/~tonyp/8086056/webrev.0/</a></div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br>
</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;">(BTW, for some
reason some of the webrev output is a bit messed up. Not sure
why, maybe some hg incompatibility I guess. The diffs look OK
though. I also attached the patch to this e-mail.)</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br>
</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;">There’s a bit
of info on the JIRA on the rationale for the patch:</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br>
</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><a
moz-do-not-send="true"
href="https://bugs.openjdk.java.net/browse/JDK-8086056">https://bugs.openjdk.java.net/browse/JDK-8086056</a></div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br>
</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;">The min / max
values for the old gen capacity and ParGCCardsPerStrideChunk
were chosen empircally after running a few (mostly synthetic
tests) on Linux x64. If someone has the cycles to do a more
extensive performance study, I’d be happy to revise them
accordingly.</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br>
</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Regards,</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;"><br>
</div>
<div id="bloop_customfont"
style="font-family:Helvetica,Arial;font-size:13px; color:
rgba(0,0,0,1.0); margin: 0px; line-height: auto;">Tony</div>
<br>
<div id="bloop_sign_1434579909530055936" class="bloop_sign">
<div style="font-family:helvetica,arial;font-size:13px">
<div>-----</div>
<div><br>
</div>
<div>Tony Printezis | JVM/GC Engineer / VM Team | Twitter</div>
<div><br>
</div>
<div>@TonyPrintezis</div>
<div><a moz-do-not-send="true"
href="mailto:tprintezis@twitter.com">tprintezis@twitter.com</a></div>
<div><br>
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