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<div class="moz-cite-prefix">On 3/9/2015 10:39 PM, Jungwoo Ha wrote:<br>
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<blockquote
cite="mid:CA+n_jhjTTzW5FMxtnUfO3pOi8KNjNU4uYqN6w9QjAuS40w722g@mail.gmail.com"
type="cite">
<div dir="ltr">We were investigating some features and figured out
that ParallelScavange and ParNew has different TenuringTreshold
heuristics.
<div>We thought it would be nice to have a flag that can control
the adaptiveness, so that we can fix it on purpose to isolate
other performance factors.</div>
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<br>
Do you use UsePSAdaptiveSurvivorSizePolicy to turn off the <br>
survivor space resizing and tenuring threshold adaptiveness<br>
for ParallelGC?<br>
<br>
Jon<br>
<br>
<blockquote
cite="mid:CA+n_jhjTTzW5FMxtnUfO3pOi8KNjNU4uYqN6w9QjAuS40w722g@mail.gmail.com"
type="cite">
<div dir="ltr">
<div>--Jungwoo</div>
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<div class="gmail_extra"><br>
<div class="gmail_quote">On Mon, Mar 9, 2015 at 11:27 AM, Jon
Masamitsu <span dir="ltr"><<a moz-do-not-send="true"
href="mailto:jon.masamitsu@oracle.com" target="_blank">jon.masamitsu@oracle.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0
.8ex;border-left:1px #ccc solid;padding-left:1ex">
<div bgcolor="#FFFFFF" text="#000000"> Jungwoo,<span
class=""><br>
<br>
<div>On 03/06/2015 06:03 PM, Jungwoo Ha wrote:<br>
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<blockquote type="cite">
<div dir="ltr">I think it is the same for all
JDK{7,8,9}.
<div><br>
</div>
<div>arguments.cpp disabled UseAdaptiveSizePolicy
for CMS.</div>
<div>parallel scavange initializes
_tenuring_threshold with</div>
<div> _tenuring_threshold = (UseAdaptiveSizePolicy)
? InitialTenuringThreshold : MaxTenuringThreshold;</div>
<div>whereas CMS uses</div>
<div> _tenuring_threshold = MaxTenuringThreshold;</div>
<div><br>
</div>
<div>adjust_desired_tenuring_threshold() is called
inside ParNewGeneration::collect(), which calls
compute_tenuring_threshold.</div>
<div>It only uses MaxTenuringThreshold and
TargetSurvivorRatio.</div>
<div>I don't see any other flags here.<br>
</div>
</div>
</blockquote>
<br>
</span> Yes, this is the intended behavior.<br>
<br>
You're saying we're sometimes wasting survivor space?<span
class="HOEnZb"><font color="#888888"><br>
<br>
Jon</font></span><span class=""><br>
<br>
<blockquote type="cite">
<div class="gmail_extra"><br>
<div class="gmail_quote">On Fri, Mar 6, 2015 at 4:28
PM, Jon Masamitsu <span dir="ltr"><<a
moz-do-not-send="true"
href="mailto:jon.masamitsu@oracle.com"
target="_blank">jon.masamitsu@oracle.com</a>></span>
wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0
0 .8ex;border-left:1px #ccc
solid;padding-left:1ex">This is in jdk9?<span><font
color="#888888"><br>
<br>
Jon</font></span>
<div>
<div><br>
<br>
On 3/6/2015 4:21 PM, Jungwoo Ha wrote:<br>
<blockquote class="gmail_quote"
style="margin:0 0 0 .8ex;border-left:1px
#ccc solid;padding-left:1ex"> On CMS when
UseAdaptiveSizePolicy is off, still
tenuring_threshold is being changed.<br>
Is this an intended behavior?<br>
(yes. I know it is not "size" related
heuristics)<br>
<br>
It would be nice to have a flag that can
disable adjusting tenuring threshold,<br>
or at least set minimum threshold. When
the default heuristics doesn't work,<br>
there are nothing much we can do other
than changing the Max.<br>
<br>
--Jungwoo<br>
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