Request for review:7133260:Remove -Xaprof and the usage of Klass:_alloc_count and ArrayKlass::_alloc_size

[Stefan Karlsson]

On 06/05/2013 04:15 AM, Jiangli Zhou wrote:
> Hi,
>
> Please review following change for 7133260.
>
>   http://ccc.us.oracle.com/7133260

I looked at:
http://cr.openjdk.java.net/~jiangli/7133260/webrev.00

Looks good. Thanks for doing this cleanup.

You remove the last usage of:
  object_iterate_since_last_GC
  with_array_klasses_do

so there's even more cleanups that can be done here.

>
> In JDK8, -Xaprof support is outdated and broken. A new feature, 
> GC.class_stats command has been added to jcmd in JDK8. It provides 
> detailed class metadata memory statistics information. -Xaprof uses 
> Klass:_alloc_count and ArrayKlass::_alloc_size. Removing -Xaprof and 
> related fields would save 4bytes per class and 8bytes per array class.

FTR, I don't think you save 8 bytes for the array classes. The size of 
ArrayKlass increased so that the vtable offset matches the vtable offset 
of the InstanceKlasses. See ArrayKlass::static_size.

thanks
StefanK

> Please see more information in the CCC request: 
> http://ccc.us.oracle.com/7133260.
>
> Tested with JPTR and vm.quick.testlist.
>
> Thanks,
> Jiangli