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Hi Chris,<br>
OK, that all sounds good. <br>
<br>
>> I can change it, although that will mean filing a new CCC.<br>
Ah, I'd forgotten about that. Not worth it, unless there's a
landslide of support for a different name.<br>
<br>
Tnx,<br>
Tom<br>
<br>
<div class="moz-cite-prefix">On 2/10/2016 3:06 PM, Chris Plummer
wrote:<br>
</div>
<blockquote cite="mid:56BB9831.5030504@oracle.com" type="cite">
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<div class="moz-cite-prefix">Hi Tom,<br>
<br>
Thanks for having a look. Comments inline below:<br>
<br>
On 2/10/16 11:27 AM, Tom Benson wrote:<br>
</div>
<blockquote cite="mid:56BB8F3D.3070502@oracle.com" type="cite">Hi
Chris, <br>
My apologies if I missed the discussion somewhere, but is there
a specific rationale for adding this that can be mentioned in
the bug report? I can imagine scenarios where it would be
useful, but maybe the real need can be called out. <br>
</blockquote>
In general, it is for customers that want to minimize the amount
of memory used by the java heap, and are willing to sacrifice some
performance (induce more frequent GCs) to save that memory. When
heap usage fluctuates greatly, the GC will tend to hold on to that
memory longer than needed due to the the current algorithm which
requires 4 full GCs before
<meta http-equiv="content-type" content="text/html; charset=utf-8">
MaxHeapFreeRatio is fully honored. If this is what you are looking
for, I can add it to the CR.<br>
<blockquote cite="mid:56BB8F3D.3070502@oracle.com" type="cite"> <br>
I think it might be clearer if the new code in cardGeneration
was moved down to where the values are used. IE, I would leave
the inits of current_shrink_factor and _shrink_factor as they
were at lines 190/191. Then down at 270, just don't divide by
the shrink factor if UseAggressiveHeapShrink is set, and the
updates to shrink factor can be in the same conditional. This
has the advantage that you can fix the comment just above it to
match this special case. Do you think that would work? <br>
</blockquote>
Yes, that makes sense. I'll get started on it. I have a vacation
coming up shortly, so what I'll get a new webrev out soon, but
probably will need to wait until after my trip to do more thorough
testing and push the changes.<br>
<blockquote cite="mid:56BB8F3D.3070502@oracle.com" type="cite"> <br>
It looks like the ending "\" at line 3330 in globals.hpp isn't
aligned, and the copyright in cardGeneration.cpp needs to be
updated. <br>
</blockquote>
Ok.<br>
<blockquote cite="mid:56BB8F3D.3070502@oracle.com" type="cite"> <br>
One other nit, which you can ignore unless someone comes forward
to agree with me 8^) , is that I'd prefer the name
ShrinkHeapAggressively instead. Maybe this was already debated
elsewhere.... <br>
</blockquote>
The name choice hasn't really been discussed or questioned. It was
what was suggested to me, so I stuck with it (The initial work was
done by someone else. I'm just getting it integrated into 9). I
can change it, although that will mean filing a new CCC.<br>
<br>
thanks,<br>
<br>
Chris<br>
<blockquote cite="mid:56BB8F3D.3070502@oracle.com" type="cite">Tom
<br>
<br>
On 2/4/2016 1:36 PM, Chris Plummer wrote: <br>
<blockquote type="cite">Hello, <br>
<br>
Please review the following for adding the -XX
UseAggressiveHeapShrink option. When turned on, it tells the
GC to reduce the heap size to the new target size immediately
after a full GC rather than doing it progressively over 4 GCs.
<br>
<br>
Webrev: <a moz-do-not-send="true"
class="moz-txt-link-freetext"
href="http://cr.openjdk.java.net/%7Ecjplummer/8146436/webrev.02/">http://cr.openjdk.java.net/~cjplummer/8146436/webrev.02/</a>
<br>
Bug: <a moz-do-not-send="true" class="moz-txt-link-freetext"
href="https://bugs.openjdk.java.net/browse/JDK-8146436">https://bugs.openjdk.java.net/browse/JDK-8146436</a>
<br>
<br>
Testing: <br>
-JPRT with '-testset hotspot' <br>
-JPRT with '-testset hotspot -vmflags
"-XX:+UseAggressiveHeapShrink"' <br>
-added new TestMaxMinHeapFreeRatioFlags.java test <br>
<br>
thanks, <br>
<br>
Chris <br>
</blockquote>
<br>
</blockquote>
<br>
</blockquote>
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