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

Yasumasa Suenaga yasuenag at gmail.com
Wed Mar 16 23:23:33 UTC 2016


Hi Jon,

2016/03/17 3:25 "Jon Masamitsu" <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
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/attachments/20160317/eabba6cb/attachment-0001.html>


More information about the hotspot-gc-dev mailing list