RFR: JDK-8151674: STW phases at Concurrent GC should count in PerfCounter

Jon Masamitsu jon.masamitsu at oracle.com
Fri Mar 18 19:45:40 UTC 2016



On 3/18/2016 7:14 AM, Yasumasa Suenaga wrote:
> Hi,
>
>> I added a comment to JBS about G1 initial mark.
>> I will upload new webrev after discussing for it.
>
> We discussed about it on JBS, and we decided not to count initial mark 
> on G1
> to CGC counter. [1]
>
> I uploaded new webrev. Could you review it?

Changes look good.   We'll need one more review of the hotspot changes.

Jon

>
>   hotspot: 
> http://cr.openjdk.java.net/~ysuenaga/JDK-8151674/webrev.01/hotspot/
>       jdk: 
> http://cr.openjdk.java.net/~ysuenaga/JDK-8151674/webrev.01/jdk/
>
> jdk part is the same with the patch which is reviewed by Staffan 
> Larsen. [2]
>
>
> Thanks,
>
> Yasumasa
>
>
> [1] 
> https://bugs.openjdk.java.net/browse/JDK-8151674?focusedCommentId=13914167&page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#comment-13914167
> [2] 
> http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-March/016911.html
>
>
> On 2016/03/17 8:23, Yasumasa Suenaga wrote:
>> Hi Jon,
>>
>> 2016/03/17 3:25 "Jon Masamitsu" <jon.masamitsu at oracle.com 
>> <mailto:jon.masamitsu at oracle.com>>:
>>  >
>>  >
>>  >
>>  > On 03/10/2016 07:59 PM, Yasumasa Suenaga wrote:
>>  >>
>>  >> Hi all,
>>  >>
>>  >> This review request continues from:
>>  >> 
>> http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-March/016774.html
>>  >> 
>> http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-March/016896.html
>>  >>
>>  >> I wonder that STW phases (Remark and Cleanup) at G1 are not 
>> counted in jstat FGC column.
>>  >> For example, Initial Mark and Remark at CMS are counted as FGC.
>>  >> We discussed on hotspot-gc-dev for this issue, and I proposed to 
>> add new PerfCounter
>>  >> for CGC STW phases.
>>  >>
>>  >> I uploaded webrev. Could you review it?
>>  >>      hotspot: 
>> http://cr.openjdk.java.net/~ysuenaga/JDK-8151674/webrev.00/hotspot/
>>  >>          jdk: 
>> http://cr.openjdk.java.net/~ysuenaga/JDK-8151674/webrev.00/jdk/
>>  >>
>>  >> For compatibility, this patch works the same as the current by 
>> default.
>>  >> If you set -XX:+EnableConcGCPerfCounter, CGC counter will work fine.
>>  >> (I want to set +EnableConcGCPerfCounter by default)
>>  >
>>  >
>>  > I would prefer not to have the flag (EnableConcGCPerfCounte)
>>  > and just make the change for CMS.  This is a change for a major
>>  > release and I think we can accept the incompatibility.
>>
>> Okay, I will remove this flag.
>>
>> I added a comment to JBS about G1 initial mark.
>> I will upload new webrev after discussing for it.
>>
>>  > 
>> http://cr.openjdk.java.net/~ysuenaga/JDK-8151674/webrev.00/hotspot/src/share/vm/gc/g1/g1MonitoringSupport.cpp.udiff.html
>>  >
>>  > + // name "collector.2". In a generational collector this would be 
>> the
>>  > + // STW phases in concurrent collection.
>>  > + _conc_collection_counters =
>>  > + new CollectorCounters("G1 stop-the-world phases", 2);
>>  >
>>  >
>>  > Is there a hard connection between these phases and a generational
>>  > collector (i.e., should the "In a generational collector this 
>> would be the"
>>  > be dropped in the comment)?
>>  >
>>  > A comment such as
>>  >
>>  > // name "collector.2". STW phases as part of a concurrent collection.
>>
>> Thanks, I will fix.
>>
>>  > A set of JDK changes had been previously been reviewed (not by 
>> me). Are these
>>  > the same?
>>  >
>>  > http://cr.openjdk.java.net/~ysuenaga/JDK-8151674/webrev.00/jdk/
>>
>> Yes, same patch.
>>
>> Yasumasa
>>
>>  > Jon
>>  >
>>  >
>>  >
>>  >>
>>  >>
>>  >> I cannot access JPRT.
>>  >> So I need a sponsor.
>>  >>
>>  >>
>>  >> Thanks,
>>  >>
>>  >> Yasumasa
>>  >
>>  >
>>



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