Request for review:7133260:Remove -Xaprof and the usage of Klass:_alloc_count and ArrayKlass::_alloc_size
stefan.karlsson at oracle.com
Wed Jun 5 01:48:21 PDT 2013
On 06/05/2013 04:15 AM, Jiangli Zhou wrote:
> Please review following change for 7133260.
I looked at:
Looks good. Thanks for doing this cleanup.
You remove the last usage of:
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 In JDK8, -Xaprof support is outdated and broken.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.
> Please see more information in the CCC request:
> Tested with JPTR and vm.quick.testlist.
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