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<div class="moz-cite-prefix">On 1/29/18 10:35 AM, mandy chung wrote:<br>
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Thanks for the reply Paul. Try to understand a little more on
the specific from gc-specific memory pool you depend on.<br>
<br>
<div class="moz-cite-prefix">On 1/29/18 8:27 AM, Hohensee, Paul
wrote:<br>
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<p class="MsoNormal">A name change would affect Amazon’s heap
monitoring, and thus I expect it would affect other users as
well.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">As long as there are gc-specific memory
pools, we’re going to need to be able to identify them, and
right now that’s done via name. </p>
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<br>
MemoryPoolMXBean::getType returns "heap" memory type for
GC-specific memory pools. Are you using this method? Do you use
the name to build in specific characteristic of a memory pool
(e.g. eden vs old gen)?<br>
<br>
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<p class="MsoNormal">All the mxbeans are identified by name,
so that’s a general design principle. The only way I can
think of to get rid of name dependency would be to figure
out what abstract metrics users want to monitor and
implement them for all collectors. HeapUsage (instantaneous
occupancy) is one, CollectionUsage (long-lived occupancy) is
another, both of these for the entire heap, not just
particular memory pools. </p>
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The sum of HeapUsage and CollectionUsage of all heap memory pools
was expected to give an incorrect approximation for the entire
heap usage. Are you seeing issue/bug with the sum result? <br>
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typo: s/an incorrect approximation/an approximation.<br>
<br>
Mandy<br>
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<blockquote type="cite"
cite="mid:af50f233-f441-caa0-625d-b90b1d4578db@oracle.com"> Mandy<br>
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cite="mid:4BA32239-D645-4B1A-A58E-502258C8FFB7@amazon.com">
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<p class="MsoNormal">That said, imo there will always be a
demand for the ability to get collector and memory pool
specific details, so I don’t see a way to get around
providing named entities.<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal">Paul<o:p></o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal"><b><span
style="font-size:12.0pt;color:black">From: </span></b><span
style="font-size:12.0pt;color:black">mandy chung <a
class="moz-txt-link-rfc2396E"
href="mailto:mandy.chung@oracle.com"
moz-do-not-send="true"><mandy.chung@oracle.com></a><br>
<b>Organization: </b>Oracle Corporation<br>
<b>Date: </b>Friday, January 26, 2018 at 2:38 PM<br>
<b>To: </b>"Hohensee, Paul" <a
class="moz-txt-link-rfc2396E"
href="mailto:hohensee@amazon.com"
moz-do-not-send="true"><hohensee@amazon.com></a>,
Erik Helin <a class="moz-txt-link-rfc2396E"
href="mailto:erik.helin@oracle.com"
moz-do-not-send="true"><erik.helin@oracle.com></a>,
David Holmes <a class="moz-txt-link-rfc2396E"
href="mailto:david.holmes@oracle.com"
moz-do-not-send="true"><david.holmes@oracle.com></a><br>
<b>Cc: </b><a class="moz-txt-link-rfc2396E"
href="mailto:serviceability-dev@openjdk.java.net"
moz-do-not-send="true">"serviceability-dev@openjdk.java.net"</a>
<a class="moz-txt-link-rfc2396E"
href="mailto:serviceability-dev@openjdk.java.net"
moz-do-not-send="true"><serviceability-dev@openjdk.java.net></a>,
<a class="moz-txt-link-rfc2396E"
href="mailto:hotspot-gc-dev@openjdk.java.net"
moz-do-not-send="true">"hotspot-gc-dev@openjdk.java.net"</a>
<a class="moz-txt-link-rfc2396E"
href="mailto:hotspot-gc-dev@openjdk.java.net"
moz-do-not-send="true"><hotspot-gc-dev@openjdk.java.net></a><br>
<b>Subject: </b>Re: RFR (S): 8195115: G1 Old Gen
MemoryPool CollectionUsage.used values don't reflect
mixed GC results<o:p></o:p></span></p>
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<p class="MsoNormal"><o:p> </o:p></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><o:p> </o:p></p>
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<p class="MsoNormal">On 1/25/18 1:04 PM, Hohensee, Paul
wrote:<o:p></o:p></p>
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<p class="MsoNormal"><br>
> The JMX API spec doesn’t specify what the memory pool
or garbage > collector names are, but the current names
are de-facto part of the > API, so if we change the
existing ones, imo a CSR should be filed.<o:p></o:p></p>
<pre>The names are implementation details but I can see how an application<o:p></o:p></pre>
<pre>might be impacted if they depend on it. CSR approval is not strictly<o:p></o:p></pre>
<pre>necessary while I think filing one to document the change would be <o:p></o:p></pre>
<pre>good.<o:p></o:p></pre>
<p class="MsoNormal"><o:p> </o:p></p>
<pre>Does the name change impact any application you know of? I'm trying to<o:p></o:p></pre>
<pre>understand if any improvement to API is needed so that applications <o:p></o:p></pre>
<pre>don't need to depend on the names.<o:p></o:p></pre>
<p class="MsoNormal"><br>
Mandy<br>
<br>
<o:p></o:p></p>
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