continuous cms gc. even though it is not hitting CMSInitiatingOccupancyFraction=68 Is thsi a know issue
Jon Masamitsu
Jon.Masamitsu at Sun.COM
Thu Nov 22 00:15:47 UTC 2007
On Nov 21, 2007, at 4:06 PM, Peter B. Kessler wrote:
> I thought Ramki was suggesting separate -
> XX:CMSInitiatingOccupancyFraction=
> and -XX:CMSPermInitiatingOccupancyFraction= options, so the permanent
> generation could get relatively more full before starting a CMS cycle.
> (And, obviously (?), if -XX:-CMSPermGenSweepingEnabled, then the
> occupancy
> of the permanent generation wouldn't figure into the decision at all.
Ok. That seems a modest enough proposal as long as the collection of
the
perm gen only uses the occupancy threshold test.
>
> ... peter
>
> Jon Masamitsu wrote:
>
>> Ramki,
>> Are you suggesting that we be able to collect the tenured gen and the
>> perm gen separately? So that in this case we would have seen the
>> continuous collections but only of the perm gen?
>> Jon
>> On Nov 21, 2007, at 2:53 PM, Y Srinivas Ramakrishna wrote:
>>>
>>> Hi Anuj --
>>>
>>> the reason is that perm gen collection is enabled and the
>>> occupancy of
>>> the perm gen has exceeded the triggering threshold. (The
>>> criterion currently
>>> is to start the collection if either perm gen or old gen
>>> occupancy exceeds the threshold.)
>>> A workaround might be to increase MaxPermSize. The JVM should
>>> clearly
>>> be more "ergonomic" about this, but even otherwise it might be
>>> desirable
>>> (what do people feel?) to somehow divorce the two thresholds
>>> (which are
>>> currently conflated as one).
>>>
>>> -- ramki.
>>>
>>> ----- Original Message -----
>>> From: Anuj Lal <alal at hotwire.com>
>>> Date: Wednesday, November 21, 2007 2:27 pm
>>> Subject: continuous cms gc. even though it is not hitting
>>> CMSInitiatingOccupancyFraction=68 Is thsi a know issue
>>> To: hotspot-gc-dev at openjdk.java.net
>>> Cc: hotspotgc-feedback at sun.com
>>>
>>>
>>>> We just moved to 1.5.0.13 from 1.4.12. It sin production.
>>>>
>>>> I am opening sun support case too.
>>>>
>>>>
>>>>
>>>> -Xms2460m -server
>>>>
>>>> -XX:+UseConcMarkSweepGC
>>>>
>>>> -XX:+UseParNewGC
>>>>
>>>> -XX:+CMSParallelRemarkEnabled
>>>>
>>>> -XX:+UseCMSCompactAtFullCollection
>>>>
>>>> -XX:CMSFullGCsBeforeCompaction=0
>>>>
>>>> -XX:+HandlePromotionFailure
>>>>
>>>> -XX:CMSInitiatingOccupancyFraction=68
>>>>
>>>> -XX:+UseCMSInitiatingOccupancyOnly
>>>>
>>>> -Xmx2460m
>>>>
>>>> -XX:NewSize=462M
>>>>
>>>> -XX:MaxNewSize=462M
>>>>
>>>> -XX:MaxTenuringThreshold=5
>>>>
>>>> -XX:SurvivorRatio=5
>>>>
>>>> -XX:TargetSurvivorRatio=80
>>>>
>>>> -XX:PermSize=256M
>>>>
>>>> -XX:MaxPermSize=256M
>>>>
>>>> -XX:-DisableExplicitGC
>>>>
>>>> -XX:+CMSPermGenSweepingEnabled
>>>>
>>>> -XX:+CMSClassUnloadingEnabled
>>>>
>>>> -XX:CMSMaxAbortablePrecleanTime=1
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Here I sthe snippet of log. See used is only used 599703K an
>>>> jvm keep
>>>> doing cms gc
>>>>
>>>>
>>>>
>>>> Anuj
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> concurrent mark-sweep generation total 2045952K, used 599703K
>>>> [0x6b600000, 0xe8400000, 0xe8400000)
>>>>
>>>> concurrent-mark-sweep perm gen total 262144K, used 182700K
>>>> [0xe8400000,
>>>> 0xf8400000, 0xf8400000)
>>>>
>>>> 474868.841: [ParNew
>>>>
>>>> Desired survivor size 55364812 bytes, new threshold 5 (max 5)
>>>>
>>>> - age 1: 11103424 bytes, 11103424 total
>>>>
>>>> - age 2: 4182448 bytes, 15285872 total
>>>>
>>>> - age 3: 6066672 bytes, 21352544 total
>>>>
>>>> - age 4: 7075376 bytes, 28427920 total
>>>>
>>>> : 363413K->27933K(405504K), 0.1678588 secs]
>>>> 963116K->627636K(2451456K)Heap after gc invocations=22744:
>>>>
>>>> par new generation total 405504K, used 27933K [0x4e800000,
>>>> 0x6b600000, 0x6b600000)
>>>>
>>>> eden space 337920K, 0% used [0x4e800000, 0x4e800000,
>>>> 0x63200000)
>>>>
>>>> from space 67584K, 41% used [0x67400000, 0x68f47550, 0x6b600000)
>>>>
>>>> to space 67584K, 0% used [0x63200000, 0x63200000, 0x67400000)
>>>>
>>>> concurrent mark-sweep generation total 2045952K, used 599703K
>>>> [0x6b600000, 0xe8400000, 0xe8400000)
>>>>
>>>> concurrent-mark-sweep perm gen total 262144K, used 182700K
>>>> [0xe8400000,
>>>> 0xf8400000, 0xf8400000)
>>>>
>>>> }
>>>>
>>>> , 0.1688079 secs]
>>>>
>>>> 474869.011: [GC [1 CMS-initial-mark: 599703K(2045952K)]
>>>> 628140K(2451456K), 0.1199002 secs]
>>>>
>>>> 474869.132: [CMS-concurrent-mark-start]
>>>>
>>>> 474876.273: [CMS-concurrent-mark: 7.004/7.141 secs]
>>>>
>>>> 474876.273: [CMS-concurrent-preclean-start]
>>>>
>>>> 474876.344: [CMS-concurrent-preclean: 0.069/0.071 secs]
>>>>
>>>> 474876.344: [CMS-concurrent-abortable-preclean-start]
>>>>
>>>> CMS: abort preclean due to time 474877.846:
>>>> [CMS-concurrent-abortable-preclean: 1.006/1.502 secs]
>>>>
>>>> 474877.854: [GC[YG occupancy: 211030 K (405504 K)]474877.854:
>>>> [Rescan
>>>> (parallel) , 0.6154592 secs]474878.470: [weak refs processing,
>>>>
>>>> 0.3838744 secs]474878.854: [class unloading, 0.1124973 secs]
>>>> 474878.966:
>>>> [scrub symbol & string tables, 0.0976109 secs] [1 CMS-remar
>>>>
>>>> k: 599703K(2045952K)] 810733K(2451456K), 1.2858288 secs]
>>>>
>>>> 474879.150: [CMS-concurrent-sweep-start]
>>>>
>>>> 474882.602: [CMS-concurrent-sweep: 3.336/3.452 secs]
>>>>
>>>> 474882.602: [CMS-concurrent-reset-start]
>>>>
>>>> 474882.846: [CMS-concurrent-reset: 0.244/0.244 secs]
>>>>
>>>> 474882.985: [GC [1 CMS-initial-mark: 595574K(2045952K)]
>>>> 897595K(2451456K), 1.2062837 secs]
>>>>
>>>> 474884.192: [CMS-concurrent-mark-start]
>>>>
>>>> 474889.371: [CMS-concurrent-mark: 5.179/5.179 secs]
>>>>
>>>> 474889.371: [CMS-concurrent-preclean-start]
>>>>
>>>> 474889.459: [CMS-concurrent-preclean: 0.084/0.088 secs]
>>>>
>>>> 474889.459: [CMS-concurrent-abortable-preclean-start]
>>>>
>>>> CMS: abort preclean due to time 474891.671:
>>>> [CMS-concurrent-abortable-preclean: 1.004/2.212 secs]
>>>>
>>>> 474891.799: [GC[YG occupancy: 330467 K (405504 K)]474891.799:
>>>> [Rescan
>>>> (parallel) , 1.0003167 secs]474892.800: [weak refs processing,
>>>>
>>>> 0.4521800 secs]474893.252: [class unloading, 0.1199606 secs]
>>>> 474893.372:
>>>> [scrub symbol & string tables, 0.1051379 secs] [1 CMS-remar
>>>>
>>>> k: 595574K(2045952K)] 926042K(2451456K), 1.7586947 secs]
>>>>
>>>> 474893.562: [CMS-concurrent-sweep-start]
>>>>
>>>> 474895.970: [CMS-concurrent-sweep: 2.408/2.408 secs]
>>>>
>>>> 474895.970: [CMS-concurrent-reset-start]
>>>>
>>>> 474896.187: [CMS-concurrent-reset: 0.217/0.217 secs]
>>>>
>>>> 474898.296: [GC [1 CMS-initial-mark: 594417K(2045952K)]
>>>> 932649K(2451456K), 1.2541899 secs]
>>>>
>>>> 474899.551: [CMS-concurrent-mark-start]
>>>>
>>>> 474904.513: [CMS-concurrent-mark: 4.962/4.962 secs]
>>>>
>>>> 474904.513: [CMS-concurrent-preclean-start]
>>>>
>>>> 474904.584: [CMS-concurrent-preclean: 0.068/0.071 secs]
>>>>
>>>> 474904.584: [CMS-concurrent-abortable-preclean-start]
>>>>
>>>> CMS: abort preclean due to time 474906.523:
>>>> [CMS-concurrent-abortable-preclean: 1.017/1.938 secs]
>>>>
>>>> 474906.549: [GC[YG occupancy: 346194 K (405504 K)]474906.549:
>>>> [Rescan
>>>> (parallel) , 1.0806458 secs]474907.630: [weak refs processing,
>>>>
>>>> 0.4560526 secs]474908.086: [class unloading, 0.1184826 secs]
>>>> 474908.205:
>>>> [scrub symbol & string tables, 0.0981007 secs] [1 CMS-remar
>>>>
>>>> k: 594417K(2045952K)] 940611K(2451456K), 1.8293189 secs]
>>>>
>>>> 474908.379: [CMS-concurrent-sweep-start]
>>>>
>>>> 474910.636: [CMS-concurrent-sweep: 2.256/2.256 secs]
>>>>
>>>> 474910.636: [CMS-concurrent-reset-start]
>>>>
>>>> 474910.782: [CMS-concurrent-reset: 0.146/0.146 secs]
>>>>
>>>> 474912.320: [GC [1 CMS-initial-mark: 594402K(2045952K)]
>>>> 949362K(2451456K), 1.2208158 secs]
>>>>
>>>> 474913.542: [CMS-concurrent-mark-start]
>>>>
>>>> 474914.002: [GC {Heap before gc invocations=22744:
>>>>
>>>> par new generation total 405504K, used 365853K [0x4e800000,
>>>> 0x6b600000, 0x6b600000)
>>>>
>>>> eden space 337920K, 100% used [0x4e800000, 0x63200000,
>>>> 0x63200000)
>>>>
>>>> from space 67584K, 41% used [0x67400000, 0x68f47550, 0x6b600000)
>>>>
>>>> to space 67584K, 0% used [0x63200000, 0x63200000, 0x67400000)
>>>>
>
>
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