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Hi Kirk - <br>
<br>
I see that Charlie has already answered that one. I'll just expand
on that... Basically *any* value of InitiatingHeapOccupancyPercent
is checked against the already allocated and current bytes. If the
total bytes are greater than heap*IHOP/100 (since IHOP is expressed
as a percent) and if young GC, then we start the concurrent cycle.
If not then we are doing mixed GC.<br>
<br>
-Monica<br>
<br>
On 10/19/2012 12:58 PM, Kirk Pepperdine wrote:
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cite="mid:1A6AB65C-E2AB-483C-9533-17BA577BA693@kodewerk.com"
type="cite">
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Hi Monica,
<div><br>
</div>
<div>Can you comment on what a value of 0 means?</div>
<div><br>
</div>
<div>Regards,</div>
<div>Kirk</div>
<div><br>
<div>
<div>On 2012-10-19, at 2:55 PM, Monica Beckwith <<a
moz-do-not-send="true"
href="mailto:monica.beckwith@oracle.com">monica.beckwith@oracle.com</a>>
wrote:</div>
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<div bgcolor="#FFFFFF" text="#000000"> Couple of quick
observations and questions - <br>
<ol>
<li>G1 is officially supported in 7u4. (There are
numerous performance improvements that I recommend
updating to the latest jdk7 update, if possible)</li>
<li>What do you mean by old gen collection? Are you
talking about MixedGCs?</li>
<li>Instead of setting InitiatingHeapOccupancyPercent to
zero, have you tried resizing your young generation?</li>
<ol>
<li>I see the NewRatio, but that fixes the nursery to
640, instead have you tried with a lower (than the
min default) of nursery using the NewSize option?</li>
</ol>
</ol>
<p>-Monica<br>
</p>
<br>
<br>
On 10/19/2012 12:13 AM, csewhiz wrote:
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cite="mid:13a7770622f.3368361147554026191.2919233442948217281@zoho.com"
type="cite">
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<div
style="font-size:10pt;font-family:Verdana,Arial,Helvetica,sans-serif;">
<div>Hello All,</div>
<div> Sorry for posting this question in this mailing
list. I am unable to find any answer for this. I am
trying to tune our application for G1GC as we need
very small pauses Below 500msec. </div>
<div> But the problem is when we are runing with G1GC
(under jdk 6_u37) Old generation of garbage
collection only happening when it is reaching the
Max GC size I noticed on jdk 6U 37 if max heap size
is 1GB then it is close to 1sec 2GB close to 2 sec
pauses. </div>
<div> </div>
<div> Is there any parameter to force the old gc
happening regularly. </div>
<div> </div>
<div>I am trying following setting, </div>
<div> </div>
<div>-Xms1280M -Xmx1280M -XX:+UseG1GC
-XX:MaxTenuringThreshold=15 -XX:SurvivorRatio=8
-XX:NewRatio=1 -XX:GCPauseIntervalMillis=7500
-XX:MaxGCPauseMillis=500
-XX:InitiatingHeapOccupancyPercent=0
-XX:ParallelGCThreads=7 -XX:ConcGCThreads=7 </div>
<div> </div>
<div>If anyone can give insight on how full GC is
triggred internals will be of great help.</div>
<div> </div>
<div>PS: I have tried without any option for G1 but
not of much help hence .. this one trying to be
agressive ? but of not much help.</div>
<div> </div>
<div> </div>
<div>Regards,</div>
<div>Soumit<br>
<br>
</div>
</div>
</blockquote>
<br>
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