Request for review (xs) - 8000325

[Jon Masamitsu]

On 11/29/2012 3:17 PM, Srinivas Ramakrishna wrote:
> Looks good. Would be great to prominently release-note this change when it
> appears in a public/GA update/release.
>
> Out of curiosity, any perf data on CMS pause time diffs from this change
> with current NPG?

I ran refworkload server_reference and saw a regression only on 
specjbb2000.  The regression was on the
remark pauses (as would be expected) and the largest I saw was about 
12%.  Larger than I would have
hoped.   The unloading is done serially so maybe things around it got 
faster.

Jon


> -- ramki
>
> On Thu, Nov 29, 2012 at 9:46 AM, Jon Masamitsu<jon.masamitsu at oracle.com>wrote:
>
>> This is a change in the default class unloading policy for CMS.
>>
>> 8000325:        Change default for CMSClassUnloadingEnabled to true
>>
>> http://cr.openjdk.java.net/~**jmasa/8000325/webrev.00/<http://cr.openjdk.java.net/%7Ejmasa/8000325/webrev.00/>
>>
>> With perm gen removal it becomes important for CMS to unload
>> classes to avoid excessive consumption of native memory for
>> metadata.
>>