Hi Yasumasa, Looks good.
Regards, Kirk > On Mar 3, 2016, at 2:23 PM, Yasumasa Suenaga <yasue...@gmail.com> wrote: > > Hi all, > > I've uploaded PoC of PerfCounter for STW phase in concurrent GC: > > hotspot: http://cr.openjdk.java.net/~ysuenaga/perfcounter-for-cgc/hotspot/ > jdk: http://cr.openjdk.java.net/~ysuenaga/perfcounter-for-cgc/jdk/ > > These patches makes new jstat column CGC and CGCT as below: > ------------- > $ jstat -gc 53494 3000 > S0C S1C S0U S1U EC EU OC OU MC > MU CCSC CCSU YGC YGCT FGC FGCT CGC CGCT GCT > 0.0 0.0 0.0 0.0 4096.0 0.0 28672.0 0.0 4480.0 > 948.9 384.0 77.6 0 0.000 0 0.000 0 0.000 0.000 > 0.0 1024.0 0.0 1024.0 3072.0 0.0 28672.0 0.0 4864.0 > 2969.0 512.0 276.0 1 0.063 0 0.000 2 0.016 0.080 > ------------- > > They are shows STW phase in concurrent GC. > > CMS: Initial Mark and Remark > G1: Remark and Cleanup > > GCT is sum of YGCT, FGCT, and CGCT. > > > Can be this change accepted? > If so, I will file it to JBS and will send RFR. > > I cannot access JPRT. > So I need a sponsor. > > > Thanks, > > Yasumasa > > > On 2016/03/02 23:19, Yasumasa Suenaga wrote: >> It is not difficult to create webrev for this proposal. >> However, this proposal affects to jstat output, and >> I cannot access JPRT. >> So I want to find sponsor for it at first. >> >> Could somebody be a sponsor? >> >> >> Yasumasa >> >> >> On 2016/03/02 22:29, k...@kodewerk.com wrote: >>> Hi Yasumasa, >>> >>> It all sounds reasonable and of course the impact on downstream tooling vs >>> the value of the change must be evaluated. In this case I think adding a >>> CGC counter makes sense especially in prep for G1 becoming default in 9. >>> >>> Regards, >>> Kirk >>> >>>> On Mar 2, 2016, at 6:58 AM, Yasumasa Suenaga <yasue...@gmail.com> wrote: >>>> >>>> Hi Kirk, >>>> >>>> Agree to you. >>>> However, I use occasional FGC counter at CMS as below: >>>> >>>> 1. Check major collection occurrence >>>> Some production systems have large memory as Java heap, >>>> and they are not set GC log. >>>> If their CPU usage becomes high, I want to check GC execution. >>>> (Of course, we have to check any other points :-) ) >>>> >>>> 2. Core image analysis >>>> If JVM is crashed, I want to check PerfCounter to know situation. >>>> (In the past, I sometimes encountered crash at GC worker thread.) >>>> >>>> I guess that I will want to check them at G1. >>>> >>>> Thus, at least, I want to add PerfCounter for CGC (and add JVMTI event >>>> hook). >>>> However, this proposal will affect to jstat spec. >>>> So I want to discuss about it before filing to JBS. >>>> >>>> >>>> Thanks, >>>> >>>> Yasumasa >>>> >>>> >>>> On 2016/03/02 19:02, k...@kodewerk.com wrote: >>>>> Hi Yasumasa, >>>>> >>>>> Good question. I’ve never considered CMS to be a Full GC. This implies >>>>> that there should be separate performance counters for CMS pause phases >>>>> as it is possible to have FGC. Of course a FGC during CMS maybe user >>>>> triggered, triggered outside a CMS cycle, interrupts a CMS cycle, or >>>>> interrupts a CMS phase. I’m not sure how much of a distinction one needs >>>>> to make here as that could be a quick broader discussion. Certainly the >>>>> purpose isn’t to recreate the GC logs in these performance counters. But >>>>> at the very least not having a distinction between full and a STW-CMS >>>>> phase is kind of misleading in my opinion. >>>>> >>>>> Regards, >>>>> Kirk >>>>> >>>>>> On Mar 1, 2016, at 5:03 PM, Yasumasa Suenaga <yasue...@gmail.com> wrote: >>>>>> >>>>>> Hi Kirk, >>>>>> >>>>>>> It is also incorrect to count initial mark and remark in CMS as a FGC. >>>>>> >>>>>> Though, how can we check execution of major collection without GC log? >>>>>> Should we add new PerfCounter for CGC (and add CGC column to jstat >>>>>> output)? >>>>>> >>>>>> >>>>>> Yasumasa >>>>>> >>>>>> >>>>>> On 2016/03/02 6:35, k...@kodewerk.com wrote: >>>>>>> Hi, >>>>>>> >>>>>>> I think it is incorrect to count remark and cleanup as FGC. They are >>>>>>> not full collections. It is also incorrect to count initial mark and >>>>>>> remark in CMS as a FGC. It is unfortunate that this is counted this way. >>>>>>> >>>>>>> Regards, >>>>>>> Kirk >>>>>>> >>>>>>>> On Mar 1, 2016, at 8:56 AM, Yasumasa Suenaga <yasue...@gmail.com> >>>>>>>> wrote: >>>>>>>> >>>>>>>> Hi all, >>>>>>>> >>>>>>>> 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. >>>>>>>> >>>>>>>> For consistency, I think that G1 STW phases should be counted as FGC. >>>>>>>> What do you think about it? >>>>>>>> >>>>>>>> If it is accepted, I will file it to JBS and will upload webrev. >>>>>>>> >>>>>>>> >>>>>>>> suggested fix: >>>>>>>> ---------------------- >>>>>>>> diff -r 8a103ba9a7b2 src/share/vm/gc/g1/g1MonitoringSupport.cpp >>>>>>>> --- a/src/share/vm/gc/g1/g1MonitoringSupport.cpp Mon Feb 29 >>>>>>>> 22:54:24 2016 +0900 >>>>>>>> +++ b/src/share/vm/gc/g1/g1MonitoringSupport.cpp Tue Mar 01 >>>>>>>> 23:43:30 2016 +0900 >>>>>>>> @@ -103,7 +103,7 @@ >>>>>>>> // name "collector.1". In a generational collector this would be >>>>>>>> the >>>>>>>> // old generation collection. >>>>>>>> _full_collection_counters = >>>>>>>> - new CollectorCounters("G1 stop-the-world full collections", 1); >>>>>>>> + new CollectorCounters("G1 stop-the-world phase", 1); >>>>>>>> >>>>>>>> // timer sampling for all counters supporting sampling only update >>>>>>>> the >>>>>>>> // used value. See the take_sample() method. G1 requires both used >>>>>>>> and >>>>>>>> diff -r 8a103ba9a7b2 src/share/vm/gc/g1/vm_operations_g1.cpp >>>>>>>> --- a/src/share/vm/gc/g1/vm_operations_g1.cpp Mon Feb 29 22:54:24 >>>>>>>> 2016 +0900 >>>>>>>> +++ b/src/share/vm/gc/g1/vm_operations_g1.cpp Tue Mar 01 23:43:30 >>>>>>>> 2016 +0900 >>>>>>>> @@ -230,6 +230,8 @@ >>>>>>>> G1CollectedHeap* g1h = G1CollectedHeap::heap(); >>>>>>>> GCTraceTime(Info, gc) t(_printGCMessage, g1h->gc_timer_cm(), >>>>>>>> GCCause::_no_gc, true); >>>>>>>> IsGCActiveMark x; >>>>>>>> + SvcGCMarker sgcm(SvcGCMarker::OTHER); >>>>>>>> + TraceCollectorStats tcs(g1h->g1mm()->full_collection_counters()); >>>>>>>> _cl->do_void(); >>>>>>>> } >>>>>>>> >>>>>>>> ---------------------- >>>>>>>> >>>>>>>> >>>>>>>> Thanks, >>>>>>>> >>>>>>>> Yasumasa >>>>>>>> >>>>>>>> >>>>>>> >>>>> >>>
