[jboss-user] [Performance Tuning] - Re: when does java release commited memory back to the OS

[noelo]

Hi Peter,
Just a query on what you have said above i.e. 

anonymous wrote : By the way, your new size setting (-Xmn) practically guarantees full GCs every time, and full GCs are about way more expensive (10 - 100 times) than minor GCs. You should set the new size to at most 1/3 the size of the heap. 

Given the following settings

anonymous wrote : -Xms150m -Xmx600m -Xmn125m
Why would it perform a full GC ? Is it because the Xms is so small ?
If the Xms and Xmx were the same i.e. 600M would the Xmn settings be ok ?

I don't mean to hijack the thread just looking for some help understanding the implications of the Xmn setting.

regards
Noel

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