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<div class="moz-cite-prefix">On 06/02/2015 08:00 AM, Jeremy Manson
wrote:<br>
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<div dir="ltr">We'd much rather it be part of OpenJDK, because it
is large and fairly complicated, so that would save us time and
energy forward porting it every year or so. It's pretty large
(for 8u45, it is a 2600 line change and touches 20 files), so it
tends to be a lengthy and complicated forward port. We would
much rather spend that time doing something more interesting.
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<div>Just posting an updated patch whenever we need to update it
would be a little annoying (although not impossible).
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<div>Hiroshi Yamauchi tried to offer it to (I think it was)
Jon Masamitsu a few years ago,</div>
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Yes, that was me.<br>
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<div> and Jon didn't know anyone with the bandwidth to review
it. <br>
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My understanding was that the change was based on a parallelization
of<br>
the serial mark-sweep-compact (used by CMS for full collections).<br>
If it was based on the parallel-old compaction used by ParallelGC,<br>
then my bad. It should have been reviewed.<br>
<br>
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<div>(It was around the same time we contributed the parallel
initial mark). <br>
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Which we accepted and works great.<br>
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<div> I believe that was when CMS was unowned for a while.
Perhaps there's a different story now? Oracle volunteers?</div>
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CMS is still unowned. <br>
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<div>(Procedural: One problem is that Hotspot reviews
have to go through someone at Oracle. We had it
written by an OpenJDK author and reviewed by a
reviewer. We've been using it in production for years
without too many headaches (although we have yet to
inflict^Wlaunch 8u45, which has the latest updates,
widely). I totally understand that Oracle folks are
the ones who have to pay the price for a bad check-in,
but it's a pretty big hurdle for us.)</div>
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It's less the up front costs as opposed to the continuing costs.<br>
<br>
Testing (for whatever reason there are intermittent failures<br>
that we see on some platforms and not others),<br>
maintenance on code for which we have a limited understanding,<br>
and performance on other platforms that we have to care about.<br>
<br>
And priorities (we have ours just as you have yours).<br>
<br>
Jon<br>
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<div>Jeremy<br>
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<div class="gmail_extra"><br>
<div class="gmail_quote">On Tue, Jun 2, 2015 at 6:12 AM, Galkin,
Ivan <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:ivan.galkin@sap.com" target="_blank">ivan.galkin@sap.com</a>></span>
wrote:<br>
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<p class="MsoNormal"><span lang="DE">Hi,</span></p>
<p class="MsoNormal"><span lang="DE"> </span></p>
<p class="MsoNormal">in the thread „JEP 248: Make G1 the
Default Garbage Collector” [1] there is an email from
Jeremy Manson, who mentions the enhancements made by
Google to improve CMS.</p>
<p class="MsoNormal">Especially the parallelizing of
full compaction is a great improvement and we at SAP
see the strong demand of it.</p>
<p class="MsoNormal"> </p>
<p>@Jeremy: Are these changes published somewhere? May
we have insight into the diffs you've made? We could
collaborate in order to try to bring your changes into
OpenJDK.</p>
<p> </p>
<p>Kind regards and thank you in advance,</p>
<p>Ivan</p>
<p> </p>
<p>[1] <a moz-do-not-send="true"
href="http://mail.openjdk.java.net/pipermail/hotspot-dev/2015-June/018740.html"
target="_blank">
http://mail.openjdk.java.net/pipermail/hotspot-dev/2015-June/018740.html</a></p>
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