PerfData counter: sun.gc.policy.generations in JDK 8

Jon Masamitsu jon.masamitsu at oracle.com
Tue Jun 2 21:16:33 UTC 2015


Ramki,

Changes look good.

I'm guessing you tested by generating the
perfdata by hand and verifying the contents
of the perfdata.  Do you think a test can
be written to verify  the change?  If you look at

test/gc/metaspace/TestMetaspacePerfCounters.java

in your repository I think that is an example that
can be followed.

It's a jtreg test.

http://openjdk.java.net/jtreg/

Jon

On 06/01/2015 11:39 AM, Srinivas Ramakrishna wrote:
> Thanks for the review of the patch for 8-dev (from the ticket), Staffan.
>
> Sorry for the delay in getting the official webrev out -- it took me a 
> while to first get set up with an hs9 repo (thanks Jon!) and then get 
> my openjdk credentials updated (thanks Mark!).
>
> Here's the webrev against hs9 for official review:-
>
> http://cr.openjdk.java.net/~ysr/JDK-8080345/webrev.00/ 
> <http://cr.openjdk.java.net/%7Eysr/JDK-8080345/webrev.00/>
>
> I built and tested the change (on both 8-dev whose patch was attached 
> with the original bug, as well as this with hs9) and verified that the 
> counter value for generations, in the perfdata file, was now 2 instead 
> of the previous 3.
>
> thanks!
> -- ramki
>
>
> On Mon, May 18, 2015 at 1:22 AM, Staffan Larsen 
> <staffan.larsen at oracle.com <mailto:staffan.larsen at oracle.com>> wrote:
>
>     Looks like a good patch to me.
>
>     /Staffan
>
>>     On 14 maj 2015, at 18:12, Srinivas Ramakrishna <ysr1729 at gmail.com
>>     <mailto:ysr1729 at gmail.com>> wrote:
>>
>>     https://bugs.openjdk.java.net/browse/JDK-8080345
>>
>>
>>
>>     On Wed, May 13, 2015 at 1:08 PM, Srinivas Ramakrishna
>>     <ysr1729 at gmail.com <mailto:ysr1729 at gmail.com>> wrote:
>>
>>
>>         With perm gen going away (and being replaced by metaspace) in
>>         JDK 8, it makes sense that the counter
>>         sun.gc.policy.generations should be "2", rather than "3".
>>         However, in JDK 8 that counter still says 3.
>>         As I understand, the intention was that this counter would
>>         allow you to (for example) know the range of
>>         the sun.gc.generation.$num.* counters describing each of $num
>>         < sun.gc.policy.generations in the heap.
>>         Recall that the erstwhile perm gen in JDK 7 used to be
>>         synonymous with sun.gc.generation.2, but the
>>         JDK 8 avatars are now sun.gc.metaspace and
>>         sun.gc.compressedclassspace.
>>
>>         The fix is simple, and I can submit a patch. Is there an
>>         existing bug for this?
>>
>>         thanks!
>>         -- ramki
>>
>>
>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/attachments/20150602/074895cf/attachment.html>


More information about the hotspot-gc-dev mailing list