RFR: JDK-8151674: STW phases at Concurrent GC should count in PerfCounter (original) (raw)

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. + conccollectioncounters = + 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: <https://mail.openjdk.org/pipermail/hotspot-gc-dev/attachments/20160317/eabba6cb/attachment.htm>

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