<div dir="ltr">Thanks, Erik. Jungwoo will take a look (he already responded to one).<div><br></div><div>Jeremy</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Nov 9, 2016 at 7:26 AM, Erik Helin <span dir="ltr"><<a href="mailto:erik.helin@oracle.com" target="_blank">erik.helin@oracle.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">Hi Jeremy,<br>
<br>
Thanks for taking notes. I have created separate email threads on <a href="mailto:hotspot-gc-dev@openjdk.java.net" target="_blank">hotspot-gc-dev@openjdk.java.ne<wbr>t</a> for three enhancements to G1 that we think will make G1 be more like CMS for the use cases discussed during the meeting. The ideas are described in:<br>
- "RFC: Throughput barriers for G1"<br>
<br>
<a href="http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-November/019215.html" rel="noreferrer" target="_blank">http://mail.openjdk.java.net/p<wbr>ipermail/hotspot-gc-dev/2016-N<wbr>ovember/019215.html</a><br>
- "RFC: Parallel full collection for G1"<br>
<br>
<a href="http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-November/019216.html" rel="noreferrer" target="_blank">http://mail.openjdk.java.net/p<wbr>ipermail/hotspot-gc-dev/2016-N<wbr>ovember/019216.html</a><br>
- "RFC: Rebuilding remembered sets during concurrent mark"<br>
<br>
<a href="http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-November/019217.html" rel="noreferrer" target="_blank">http://mail.openjdk.java.net/p<wbr>ipermail/hotspot-gc-dev/2016-N<wbr>ovember/019217.html</a><br>
<br>
Please respond to these ideas in the respective email thread. We would be happy to help out with the design and integration if you and/or any external contributor would like too look into any (or all) of these ideas.<br>
<br>
Thanks,<br>
Erik<span class=""><br>
<br>
On 10/21/2016 08:37 PM, Jeremy Manson wrote:<br>
</span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
Hi folks,<br>
<br>
We had the face to face at JavaOne on 9/20. I took notes, which are<br>
linked from the bug:<br>
<br>
<a href="https://bugs.openjdk.java.net/browse/JDK-8142518" rel="noreferrer" target="_blank">https://bugs.openjdk.java.net/<wbr>browse/JDK-8142518</a><br>
<<a href="https://bugs.openjdk.java.net/browse/JDK-8142518" rel="noreferrer" target="_blank">https://bugs.openjdk.java.net<wbr>/browse/JDK-8142518</a>><br>
<br>
(Sorry about the delay - anything that happens at a quarterly boundary<br>
takes me twice as long because of the Google planning cycle).<br>
<br>
The current plan for followup includes Erik Helin figuring out what<br>
extracting CMS code from Hotspot will actually look like, and Paul Su<br>
providing a list of ideas for helping G1 close the performance gap. See<br>
meeting notes for more followup actions.<br>
<br>
We didn't specify a timeline for the next meeting. Paul (cc'd) said he<br>
had to go do some due diligence about getting the list of ideas. It<br>
would be great if he and / or Erik could talk about when a good time for<br>
the next sync would be.<br>
<br>
Jeremy<br>
<br>
On Sat, Aug 27, 2016 at 5:42 PM, Jeremy Manson <<a href="mailto:jeremymanson@google.com" target="_blank">jeremymanson@google.com</a><br></span><div><div class="h5">
<mailto:<a href="mailto:jeremymanson@google.com" target="_blank">jeremymanson@google.co<wbr>m</a>>> wrote:<br>
<br>
Thanks, Jon.<br>
<br>
If we are going to do it, I'd (selfishly) like to see it done<br>
earlier in the JDK 10 time frame, so that we can start contributing<br>
our patches for it for JDK 10 earlier, rather than later. But JDK<br>
10 time frame is fine.<br>
<br>
Assuming you are asking me about management issues: I just<br>
(Thursday) got back from the vacation I mentioned, so I've only just<br>
spoken about it with our management. Naturally, no immediate<br>
answer, but there's a lot of interest, and we plan to have more<br>
conversations in the near term.<br>
<br>
For a variety of reasons (most of which I've already articulated), I<br>
strongly believe we will have to do *something*, and it will mostly<br>
be a question of whether this is the right path. Since we have<br>
~three years before the issue becomes immediate, that gives us a bit<br>
of breathing room to do the right thing. Other possibilities<br>
include spending the time until JDK 10 making G1 do what we need, or<br>
figuring out another GC entirely (we'd want to evaluate, e.g.,<br>
Shenandoah).<br>
<br>
(Since the G1 possibility is clearly of interest to you folks: We<br>
would have to decide a) that it is technically feasible, and b) that<br>
you folks were likely to take the patches. In addition to finding a<br>
path forward to lowering the cost of the write barrier dramatically<br>
and dealing with the memory footprint issues (not sure this is<br>
possible), we would also have to reimplement, e.g., our parallel<br>
Full GC patch, as well as a number of other changes we've made to<br>
CMS locally.)<br>
<br>
I'd like what we end up doing to be something palatable to the<br>
community, since CMS is obviously filling a very important role in<br>
the ecosystem that won't get filled if it gets abandoned.<br>
<br>
Jeremy<br>
<br>
On Tue, Aug 23, 2016 at 9:23 PM, Jon Masamitsu<br></div></div><div><div class="h5">
<<a href="mailto:jon.masamitsu@oracle.com" target="_blank">jon.masamitsu@oracle.com</a> <mailto:<a href="mailto:jon.masamitsu@oracle.com" target="_blank">jon.masamitsu@oracle.c<wbr>om</a>>> wrote:<br>
<br>
All,<br>
<br>
I've been working on the examples and we're been discussing<br>
(arguing)<br>
about them here. They are failing into at least the following<br>
classes<br>
<br>
- Use inheritance to specialize for CMS (specialize card table is<br>
envisioned as an example).<br>
- Use a GC Interface to request something different for CMS<br>
(different write<br>
barriers for example).<br>
- Compile code under macros<br>
Similar to INCLUDE_ALL_GCS<br>
Leaves calls to specialized CMS code visible in the shared code<br>
Involves some code refactoring<br>
- Move more code to the cms directory (ParNew for example)<br>
- Custom solutions which might use one or more of the above<br>
techniques.<br>
- Argument processing I don't know about yet.<br>
<br>
We're still arguing about the example so they're not here.<br>
<br>
As I've said Oracle would not drop support of CMS until at least<br>
jdk 10 so working on separating out the code would be work<br>
for the jdk 10 time frame. Do people have reasons to get that<br>
done earlier rather than later?<br>
<br>
Also is your management's support for spending engineering time<br>
on this effort a slam-dunk? Or a qualified maybe? I'm trying to<br>
get a feel for how real this CMS project is.<br>
<br>
Jon<br>
<br>
<br>
<br>
On 8/1/2016 1:49 PM, Jeremy Manson wrote:<br>
</div></div><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><div><div class="h5">
For those following along at home, the meeting happened last<br>
week. We took notes, which are linked from the bug:<br>
<br>
<a href="https://bugs.openjdk.java.net/browse/JDK-8142518" rel="noreferrer" target="_blank">https://bugs.openjdk.java.net/<wbr>browse/JDK-8142518</a><br>
<<a href="https://bugs.openjdk.java.net/browse/JDK-8142518" rel="noreferrer" target="_blank">https://bugs.openjdk.java.net<wbr>/browse/JDK-8142518</a>><br>
<br>
The current plan for followup is to set up a meeting for the<br>
end of August, and then a f2f during JavaOne.<br>
<br>
Jeremy<br>
<br>
On Thu, Jul 21, 2016 at 9:46 AM, Jeremy Manson<br></div></div><span class="">
<<a href="mailto:jeremymanson@google.com" target="_blank">jeremymanson@google.com</a> <mailto:<a href="mailto:jeremymanson@google.com" target="_blank">jeremymanson@google.co<wbr>m</a>>> wrote:<br>
<br>
I was drafting an agenda. My expectation is that the<br>
meeting will go something like this:<br>
<br>
Introductions<br>
<br>
Discussion of motivations for JEP 291 (Jon M)<br>
<br>
Discussions of concerns about JEP 291 (roundtable)<br>
<br>
Discussion / Brainstorming about potential ways forward,<br>
as well as an understanding of what level of commitment<br>
organizations are willing to make.<br>
<br>
Discussion of action items and followup.<br>
<br>
Jeremy<br>
<br>
<br>
On Thu, Jul 21, 2016 at 7:39 AM, Martijn Verburg<br>
<<a href="mailto:martijnverburg@gmail.com" target="_blank">martijnverburg@gmail.com</a><br></span><span class="">
<mailto:<a href="mailto:martijnverburg@gmail.com" target="_blank">martijnverburg@gmail.c<wbr>om</a>>> wrote:<br>
<br>
Hi Jon,<br>
<br>
For me it's to see if there are enough folks who are<br>
willing *and* capable (to be blunt, it will need the<br>
backing of large companies) of maintaining CMS as a<br>
collector going forwards (it's important to several of<br>
our customers). If that's a yes then I'd hope to have<br>
a technical discussion around the options of how we<br>
could achieve that without causing a major headache<br>
for the Oracle GC engineers.<br>
<br>
<br>
Cheers,<br>
Martijn<br>
<br>
On 20 July 2016 at 23:50, Jon Masamitsu<br>
<<a href="mailto:jon.masamitsu@oracle.com" target="_blank">jon.masamitsu@oracle.com</a><br></span><span class="">
<mailto:<a href="mailto:jon.masamitsu@oracle.com" target="_blank">jon.masamitsu@oracle.c<wbr>om</a>>> wrote:<br>
<br>
What are peoples expectations for this meeting?<br>
<br>
Jon<br>
<br>
On 07/18/2016 10:16 AM, Jeremy Manson wrote:<br>
</span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
Presumably, everyone will be happy with meeting<br>
notes rather than an actual recording.<br>
<br>
Otherwise, I'll add:<br>
<br></span>
<a href="mailto:ysr1729@gmail.com" target="_blank">ysr1729@gmail.com</a> <mailto:<a href="mailto:ysr1729@gmail.com" target="_blank">ysr1729@gmail.com</a>><br>
<a href="mailto:mark.reinhold@oracle.com" target="_blank">mark.reinhold@oracle.com</a><br>
<mailto:<a href="mailto:mark.reinhold@oracle.com" target="_blank">mark.reinhold@oracle.c<wbr>om</a>><span class=""><br>
<br>
<br>
<br>
On Mon, Jul 18, 2016 at 8:13 AM,<br>
<a href="mailto:kirk.pepperdine@gmail.com" target="_blank">kirk.pepperdine@gmail.com</a><br></span>
<mailto:<a href="mailto:kirk.pepperdine@gmail.com" target="_blank">kirk.pepperdine@gmail.<wbr>com</a>><br>
<<a href="mailto:kirk.pepperdine@gmail.com" target="_blank">kirk.pepperdine@gmail.com</a><span class=""><br>
<mailto:<a href="mailto:kirk.pepperdine@gmail.com" target="_blank">kirk.pepperdine@gmail.<wbr>com</a>>> wrote:<br>
<br>
ok we can record if everyone is open to that.<br>
<br>
</span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
On Jul 18, 2016, at 7:48 AM, Jeremy Manson<br>
<<a href="mailto:jeremymanson@google.com" target="_blank">jeremymanson@google.com</a><br></span><span class="">
<mailto:<a href="mailto:jeremymanson@google.com" target="_blank">jeremymanson@google.co<wbr>m</a>>> wrote:<br>
<br>
Richard - I'll bring someone who can take<br>
readable notes. :)<br>
<br>
Jeremy<br>
<br>
On Sat, Jul 16, 2016 at 5:07 AM,<br>
<a href="mailto:kirk.pepperdine@gmail.com" target="_blank">kirk.pepperdine@gmail.com</a><br></span>
<mailto:<a href="mailto:kirk.pepperdine@gmail.com" target="_blank">kirk.pepperdine@gmail.<wbr>com</a>><br>
<<a href="mailto:kirk.pepperdine@gmail.com" target="_blank">kirk.pepperdine@gmail.com</a><span class=""><br>
<mailto:<a href="mailto:kirk.pepperdine@gmail.com" target="_blank">kirk.pepperdine@gmail.<wbr>com</a>>> wrote:<br>
<br>
Hi Richard,<br>
<br>
I think it’s in everyone’s interest to<br>
keep this out in the open.<br>
<br>
Kind regards,<br>
Kirk<br>
<br>
</span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
On Jul 16, 2016, at 1:34 AM, Richard<br>
Warburton <<a href="mailto:richard.warburton@gmail.com" target="_blank">richard.warburton@gmail.com</a><br></span>
<mailto:<a href="mailto:richard.warburton@gmail.com" target="_blank">richard.warburton@gmai<wbr>l.com</a>>><span class=""><br>
wrote:<br>
<br>
Hi,<br>
<br>
Sounds as if the consensus is a<br>
telephone / video conference in the<br>
near term, and then a F2F during /<br>
close to JavaOne.<br>
<br>
People who want to be invited include:<br>
<br>
<a href="mailto:kirk@kodewerk.com" target="_blank">kirk@kodewerk.com</a><br></span>
<mailto:<a href="mailto:kirk@kodewerk.com" target="_blank">kirk@kodewerk.com</a>><br>
<a href="mailto:aph@redhat.com" target="_blank">aph@redhat.com</a> <mailto:<a href="mailto:aph@redhat.com" target="_blank">aph@redhat.com</a>><br>
<a href="mailto:volker.simonis@gmail.com" target="_blank">volker.simonis@gmail.com</a><br>
<mailto:<a href="mailto:volker.simonis@gmail.com" target="_blank">volker.simonis@gmail.c<wbr>om</a>><br>
<a href="mailto:jon.masamitsu@oracle.com" target="_blank">jon.masamitsu@oracle.com</a><br>
<mailto:<a href="mailto:jon.masamitsu@oracle.com" target="_blank">jon.masamitsu@oracle.c<wbr>om</a>><br>
<a href="mailto:jeremymanson@google.com" target="_blank">jeremymanson@google.com</a><br>
<mailto:<a href="mailto:jeremymanson@google.com" target="_blank">jeremymanson@google.co<wbr>m</a>><br>
<a href="mailto:martijnverburg@gmail.com" target="_blank">martijnverburg@gmail.com</a><br>
<mailto:<a href="mailto:martijnverburg@gmail.com" target="_blank">martijnverburg@gmail.c<wbr>om</a>><br>
<a href="mailto:jwha@google.com" target="_blank">jwha@google.com</a><br>
<mailto:<a href="mailto:jwha@google.com" target="_blank">jwha@google.com</a>><span class=""><br>
<br>
Did I miss anyone? We can take<br>
date / time planning and logistics<br>
off-list.<br>
<br>
<br>
Given that this change affects a lot of<br>
organisations and people in the wider<br>
Java community I think it would be<br>
really appreciated that a brief summary<br>
of the discussion be published<br>
somewhere in public. Maybe this mailing<br>
list?<br>
<br>
regards,<br>
<br>
Richard Warburton<br>
<br>
<a href="http://insightfullogic.com" rel="noreferrer" target="_blank">http://insightfullogic.com</a><br>
@RichardWarburto<br></span>
<<a href="http://twitter.com/richardwarburto" rel="noreferrer" target="_blank">http://twitter.com/richardwar<wbr>burto</a>><br>
</blockquote>
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</blockquote>
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<br>
</blockquote>
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<br>
<br>
<br>
</blockquote>
<br>
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</blockquote>
</blockquote></div><br></div>