continuous cms gc. even though it is not hitting CMSInitiatingOccupancyFraction=68 Is thsi a know issue
Y Srinivas Ramakrishna
Y.S.Ramakrishna at Sun.COM
Wed Nov 21 23:28:03 UTC 2007
> Or we can disable perm gen collection
Only if you know for sure that there is bounded allocation in the perm
gen over the life of the run. Also beware that otherwise disabling perm gen
collection can lead to stop world pauses to collect the perm gen
which might compromise GC pause times...
> Even if we increase Max perm size we might hit issue again
Only if there's a memory leak leading to the perm gen occupancy
never stabilizing.
-- ramki.
> anuj
>
> -----Original Message-----
> From: Y Srinivas Ramakrishna [mailto:Y.S.Ramakrishna at Sun.COM]
> Sent: Wednesday, November 21, 2007 2:53 PM
> To: Anuj Lal
> Cc: hotspot-gc-dev at openjdk.java.net
> Subject: Re: continuous cms gc. even though it is not hitting
> CMSInitiatingOccupancyFraction=68 Is thsi a know issue
>
>
> 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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