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<div dir="ltr"><font face="Tahoma" color="#000000" size="2">I see. Is this the order of precedence?:</font></div>
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<div dir="ltr"><font face="tahoma" size="2">-Xmn > (-XX:NewSize -XX:MaxNewSize) > -XX:NewRatio</font></div>
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<div dir="ltr"><font face="times new roman">victor</font></div>
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<font face="Tahoma" size="2"><b>From:</b> Michael Finocchiaro [michael.finocchiaro@gmail.com]<br>
<b>Sent:</b> Sunday, December 14, 2008 10:56 AM<br>
<b>To:</b> Victor Cheung<br>
<b>Subject:</b> Re: option combinations<br>
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<div>Personally, I'd go with Xmn as dynamic resizing of New is not generally a good idea unless you are using Java7 and G3 and since I previously mentioned that NewRatio is overridden by almost every other parameter and is HIGHLY untrustworthy.<br>
Cheers,<br>
Fino<br>
<br clear="all">
Michael Finocchiaro<br>
<a href="mailto:michael.finocchiaro@gmail.com">michael.finocchiaro@gmail.com</a><br>
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<div class="gmail_quote">On Sun, Dec 14, 2008 at 4:51 PM, Victor Cheung <span dir="ltr">
<<a href="mailto:VictorC@ganz.com">VictorC@ganz.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0pt 0pt 0pt 0.8ex; BORDER-LEFT: rgb(204,204,204) 1px solid">
Regarding sizing the young generation, I seem to remember reading that the order the options are defined matters, and that the last one defined wins... so if you had "-Xmn=256m -XX:NewRatio=3 -XX:NewSize=128m" the winner is 128m. Can anyone confirm this?
(if this is not true, then what is the overriding order of these options to set the young generation size?)<br>
<br>
incidentally, are there more ways to set the young generation size?<br>
<div class="Ih2E3d"><br>
victor<br>
<br>
________________________________________<br>
From: Michael Finocchiaro [<a href="mailto:michael.finocchiaro@gmail.com">michael.finocchiaro@gmail.com</a>]<br>
Sent: Sunday, December 14, 2008 2:48 AM<br>
To: Y Srinivas Ramakrishna<br>
</div>
Cc: Victor Cheung; <a href="mailto:hotspot-gc-use@openjdk.java.net">hotspot-gc-use@openjdk.java.net</a><br>
Subject: Re: option combinations<br>
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<div></div>
<div class="Wj3C7c"><br>
I have found that NewRatio is overridden by almost any other flag and<br>
that it is recommended to use Xmn instead.<br>
Also beware that CMS will set SurvivorRatio=1024 but that you can<br>
specify SurvivorRatio explicitly to override this.<br>
All ParNewGC/CMS flags are unique to the low-pause collector (same<br>
goes for ParallelGC/ParallelOldGC for the throughout collector) except<br>
as Ramki said ParallelGCThreads.<br>
I think that Java6 gave us control for the CMSThreads or am I mistaken?<br>
Cheers,<br>
Fino<br>
<br>
Sent from Fino's iPhone 3G<br>
<br>
On 14 déc. 08, at 08:40, Y Srinivas Ramakrishna<br>
<Y.S.Ramakrishna@Sun.COM> wrote:<br>
<br>
><br>
>> i can't seem to find a comprehensive listing or matrix of which<br>
>> options are valid with each other.<br>
>><br>
>> does anyone know of such information?<br>
><br>
> Unfortunately, no such documentation exists, as far as i know.<br>
><br>
> If you have questions about specific combinations, we can try and<br>
> answer them.<br>
><br>
> We can, of course, also think about how one might go about<br>
> documenting this combinatorial morass. Any suggestions/examples?<br>
> (The general problem of transcription of the combinatorial<br>
> possibilities is of course intractable, but the problem may well<br>
> be tractable for HotSpot options by means of partitioning into<br>
> orthogonal<br>
> subsets/"partitions".)<br>
><br>
> -- ramki<br>
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