continuous cms gc. even though it is not hitting CMSInitiatingOccupancyFraction=68 Is thsi a know issue
Thomas Viessmann
Thomas.Viessmann at Sun.COM
Fri Nov 23 09:00:06 UTC 2007
Hi Ramki,
IMO permspace collection should not be triggered by the CMS threshold at
all.
Or at least not before it's 90% full. Otherwise, if the CMS threshhold
was relatively
low, Permspace would have to be wasted. A problem in particular for 32 bit
applications.
Thomas
Y Srinivas Ramakrishna schrieb:
> 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)
>>
>>
--
---
mit freundlichen Gruessen / with kind regards
Thomas Viessmann
Global Sales and Services - Software Support Engineering
Sun Microsystems GmbH Phone: +49 (0)89 46008 2365 / x62365
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