Reduce cap on maximum heap size?

Tony Printezis tony.printezis at
Thu Nov 10 04:52:42 PST 2011


compressed oops should have similar performance to the 32-bit JVM in 
most situations (you lose some given that the JVM still uses 64-bit 
references, you gain some given that 64-bit architectures typically have 
more registers available to the JIT compiler).

With regards to capping the default heap size: this is a policy for 
which whatever we do we just cannot please everyone. I'm sure there will 
be lots of people on this list that in fact will tell us NOT to cap it 
(or increase it to take up most of the machine's physical memory). So, 
if you'd like a smaller heap size (or the 32-bit JVM) please use the 
appropriate parameters when you launch the JVM.



On 11/10/2011 07:23 AM, Florian Weimer wrote:
> It seems that in OpenJDK 7, there isn't a useful limit on the
> automatically configured maximum heap size.  With 48 GB on a Linux
> system (amd64), the default choice is 12 GB, which means that scaled
> compressed oops which have a performance impact are used, as far as I
> understand it.
> Would it make sense to cap the maximum heap size around 1.5 GB instead?

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