<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
</head>
<body text="#000000" bgcolor="#FFFFFF">
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>
</div>
<blockquote type="cite"
cite="mid:4BA32239-D645-4B1A-A58E-502258C8FFB7@amazon.com">
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="Title" content="">
<meta name="Keywords" content="">
<meta name="Generator" content="Microsoft Word 15 (filtered
medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Courier New";
panose-1:2 7 3 9 2 2 5 2 4 4;}
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
pre
{mso-style-priority:99;
mso-style-link:"HTML Preformatted Char";
margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New",serif;}
span.HTMLPreformattedChar
{mso-style-name:"HTML Preformatted Char";
mso-style-priority:99;
mso-style-link:"HTML Preformatted";
font-family:"Courier",serif;}
span.EmailStyle19
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
span.msoIns
{mso-style-type:export-only;
mso-style-name:"";
text-decoration:underline;
color:teal;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style>
<div class="WordSection1">
<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>
</div>
</blockquote>
<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>
<br>
<blockquote type="cite"
cite="mid:4BA32239-D645-4B1A-A58E-502258C8FFB7@amazon.com">
<div class="WordSection1">
<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>
</div>
</blockquote>
<br>
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>
<br>
Mandy<br>
<br>
<blockquote type="cite"
cite="mid:4BA32239-D645-4B1A-A58E-502258C8FFB7@amazon.com">
<div class="WordSection1">
<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>
<div style="border:none;border-top:solid #B5C4DF
1.0pt;padding:3.0pt 0in 0in 0in">
<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"><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"><hohensee@amazon.com></a>,
Erik Helin <a class="moz-txt-link-rfc2396E" href="mailto:erik.helin@oracle.com"><erik.helin@oracle.com></a>, David Holmes
<a class="moz-txt-link-rfc2396E" href="mailto:david.holmes@oracle.com"><david.holmes@oracle.com></a><br>
<b>Cc: </b><a class="moz-txt-link-rfc2396E" href="mailto:serviceability-dev@openjdk.java.net">"serviceability-dev@openjdk.java.net"</a>
<a class="moz-txt-link-rfc2396E" href="mailto:serviceability-dev@openjdk.java.net"><serviceability-dev@openjdk.java.net></a>,
<a class="moz-txt-link-rfc2396E" href="mailto:hotspot-gc-dev@openjdk.java.net">"hotspot-gc-dev@openjdk.java.net"</a>
<a class="moz-txt-link-rfc2396E" href="mailto:hotspot-gc-dev@openjdk.java.net"><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>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<p class="MsoNormal" style="margin-bottom:12.0pt"><o:p> </o:p></p>
<div>
<p class="MsoNormal">On 1/25/18 1:04 PM, Hohensee, Paul wrote:<o:p></o:p></p>
</div>
<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>
</div>
</blockquote>
<br>
</body>
</html>