PING: RFR: JDK-8153333: [REDO] STW phases at Concurrent GC should count in PerfCounter

Stefan Johansson stefan.johansson at oracle.com
Mon Feb 5 15:33:00 UTC 2018



On 2018-02-03 06:40, Yasumasa Suenaga wrote:
> On 2018/02/02 23:38, Stefan Johansson wrote:
>> Hi Yasumasa,
>>
>> The changes doesn't apply clean on the latest jdk/hs, can you provide 
>> an updated webrev?
>
> I uploaded webrev for jdk-hs:
>   cr.openjdk.java.net/~ysuenaga/JDK-8153333/webrev.05/
>
Thanks, I've kicked off a testing job now to verify nothing unexpected 
fails.
>
>> The testing done by the submit repo doesn't cover the tests you have 
>> update so I plan to take the change for a spin and make sure the 
>> correct tests are run and verified in Mach 5.
>
> I've also tested hotspot/jtreg/:hotspot_serviceability and 
> jdk/:jdk_tools on my laptop.
> I did not see any errors / failures which are related to this change.
I also ran some local tests on this and it looks good.
>
>
>> Also a question about the change. Why do we need a special flag for 
>> CMS? I see that the original bug report refers to the flag as being a 
>> way to turn on and off the feature but the current implementation 
>> only consider the flag for CMS.
>
> http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-March/016774.html 
>
>
> Originally, STW phases (Remark and Cleanup) at G1 are not counted in 
> jstat FGC column.
> So I think we need not to control the behavior of PerfCounter for G1.
>
I agree, for G1 this should not be controlled. Maybe I was a bit 
unclear, I was wondering why we want to control it for CMS. I think 
either we should change the behavior without guarding it by a flag or 
just skip updating CMS (and leave the pauses in FGC). If we do the 
change for CMS, we should probably also do a CSR, but that should be 
fairly straight forward.

I also found the old review thread where Jon M had the same comment 
(removing the flag) and it looks like all agreed on that:
http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/2016-March/017118.html

Thanks,
Stefan

>
> Thanks,
>
> Yasumasa
>
>
>> Thanks,
>> Stefan
>>
>> On 2018-02-01 14:58, Yasumasa Suenaga wrote:
>>> PING: Could you review and sponsor it?
>>>
>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8153333/webrev.04/
>>>
>>> This change has been passed Mach 5 via submit repo:
>>> http://java.se.oracle.com:10065/mdash/jobs/mach5-one-ysuenaga-JDK-8153333-20180201-0805-10101 
>>>
>>>
>>>
>>> Thanks,
>>>
>>> Yasumasa
>>>
>>>
>>> On 2017/11/01 22:02, Yasumasa Suenaga wrote:
>>>> PING: Could you review and sponsor it?
>>>>
>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8153333/webrev.04/
>>>>
>>>> Also I need JPRT results of this change.
>>>> Could you cooperate?
>>>>
>>>>
>>>> Thanks,
>>>>
>>>> Yasumasa
>>>>
>>>>
>>>> On 2017/09/27 0:08, Yasumasa Suenaga wrote:
>>>>> Hi all,
>>>>>
>>>>> I uploaded new webrev to be adapted to jdk10/hs:
>>>>>
>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8153333/webrev.04/
>>>>>
>>>>> I want to check this patch via JPRT, but I cannot access it.
>>>>> Could you cooperate?
>>>>>
>>>>>
>>>>> Thanks,
>>>>>
>>>>> yasumasa
>>>>>
>>>>>
>>>>> On 2017/09/21 7:46, Yasumasa Suenaga wrote:
>>>>>> PING:
>>>>>>
>>>>>> Have you checked this issue?
>>>>>>
>>>>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8153333/webrev.03/hotspot/ 
>>>>>>>>
>>>>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8153333/webrev.03/jdk/
>>>>>>
>>>>>>
>>>>>> Yasumasa
>>>>>>
>>>>>>
>>>>>> On 2017/07/01 23:44, Yasumasa Suenaga wrote:
>>>>>>> PING:
>>>>>>>
>>>>>>> Have you checked this issue?
>>>>>>>
>>>>>>>
>>>>>>> Yasumasa
>>>>>>>
>>>>>>>
>>>>>>> On 2017/06/14 13:22, Yasumasa Suenaga wrote:
>>>>>>>> Hi all,
>>>>>>>>
>>>>>>>> I changed PerfCounter to show CGC STW phase in jstat in 
>>>>>>>> JDK-8151674.
>>>>>>>> However, it occurred several jtreg test failure, so it was 
>>>>>>>> back-outed.
>>>>>>>>
>>>>>>>> I want to resume to work for this issue.
>>>>>>>>
>>>>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8153333/webrev.03/hotspot/ 
>>>>>>>>
>>>>>>>> http://cr.openjdk.java.net/~ysuenaga/JDK-8153333/webrev.03/jdk/
>>>>>>>>
>>>>>>>> These changes are work fine on jtreg test as below:
>>>>>>>>
>>>>>>>>    hotspot/test/serviceability/tmtools/jstat
>>>>>>>>    jdk/test/sun/tools
>>>>>>>>
>>>>>>>>
>>>>>>>> Since JDK 9, default GC algorithm is set to G1.
>>>>>>>> So I think this change is useful to watch GC behavior through 
>>>>>>>> jstat.
>>>>>>>>
>>>>>>>> I cannot access JPRT. Could you help?
>>>>>>>>
>>>>>>>>
>>>>>>>> Thanks,
>>>>>>>>
>>>>>>>> Yasumasa
>>>>>>>>
>>



More information about the hotspot-gc-dev mailing list