Peter Johnson [http://community.jboss.org/people/peterj] replied to the 
discussion

"Memory consumption 1h after JBoss start"

To view the discussion, visit: http://community.jboss.org/message/554214#554214

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I ageee that your explanation of setting MaxTenuringThreshold to 0 is the 
commonly accepted advice. But of course, I disagree  :D 

The problem with setting MaxTenuringThreshold to 0 is that at the time the 
minor GC takes place you will have a lot of temporary objects that are still in 
use being promoted to the tenured generation. Then the tenured generation fills 
up quicker and you end up doing major CMS collections more often. It is usually 
better to let objects bounce around a few times between the survivor spaces in 
order to sift out objects that survive only a few collections and are then 
discarded, thus ensuring that only object that plan to stay around for a while 
get tenured.Tenuring temporary object is much more expensive than not tenuring 
long-lived objects.

Test I have done show that the minor collection time, even with 
MaxTenuringThreshold not set to 0, is consistently less that the two pauses 
times caused by the CMS collectior for a major collection. In addtion, having 
MaxTenuringThreshold set to a non-zero value has, in my tests, always 
outperfomed setting MaxTenuringThreshold to 0 (higher throughput, lower 
response times). At least, that is what I have observed in the many load tests 
that I have performed.

Of course, all apps are different - the reader is urged to perform his or her 
own load tests to see how their apps respond.

And Ruchir, I agree with you that discussions like this are benefitial to the 
community. :)  Hopefully the readers can take our two views into consideration 
and find what works best for their apps.

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