problem in gc with incremental mode

Y. S. Ramakrishna y.s.ramakrishna at oracle.com
Thu Nov 4 09:51:39 PDT 2010


Hi Dori --

What's the version of JDK you are running? Can you share a complete log?
It appears as though the iCMS "auto-pacing" is, for some reason, not
kicking in "soon enough"; one workaround is to use turn off auto-pacing
and use an explicit duty-cycle (which has its own disadvantages).

I'd suggest filing a bug, and including a complete log file showing
the problem.

thanks.
-- ramki

On 11/04/10 06:27, Rabin Dori wrote:
> Hi,
> 
> Once in a while and for a reason I cannot understand the CMS kicks up 
> too late which causes a promotion failure and full GC that takes very 
> long (more than 2 minutes which causes other problems)…
> 
> My question is how to tune the gc flags in order to make sure that the 
> concurrent sweep will always occur in parallel (incremental mode) 
> without long pause stop the world but also without reaching its maximum 
> capacity ?
> 
>  
> 
> (I know that in my case the *CMSInitiatingOccupancyFraction*=60 is 
> ignored because of the CMSIncrementalMode
> 
> And from looking in the log file we can see that the old generation 
> reaches size of 835’959K out of 843’000K at the time the concurrent 
> failure (I marked this line in red)
> 
>  
> 
> *_I am running the jvm with the following parameters :_*
> 
> wrapper.java.additional.4=-XX:NewSize=200m
> 
> wrapper.java.additional.5=-XX:SurvivorRatio=6
> 
> wrapper.java.additional.6=-XX:MaxTenuringThreshold=4
> 
> wrapper.java.additional.7=-XX:+CMSIncrementalMode
> 
> wrapper.java.additional.8=-XX:+CMSIncrementalPacing
> 
> wrapper.java.additional.9=-XX:+DisableExplicitGC
> 
> wrapper.java.additional.10=-XX:+UseConcMarkSweepGC
> 
> wrapper.java.additional.11=-XX:+CMSClassUnloadingEnabled
> 
> wrapper.java.additional.12=-XX:+PrintGCDetails
> 
> wrapper.java.additional.13=-XX:+PrintGCTimeStamps
> 
> wrapper.java.additional.14=-XX:-TraceClassUnloading
> 
> wrapper.java.additional.15=-XX:+HeapDumpOnOutOfMemoryError
> 
> wrapper.java.additional.16=-verbose:gc
> 
> wrapper.java.additional.17=-XX:CMSInitiatingOccupancyFraction=60
> 
> wrapper.java.additional.18=-XX:+UseCMSInitiatingOccupancyOnly
> 
> wrapper.java.additional.19=-XX:+PrintTenuringDistribution
> 
>  
> 
>  
> 
> *_Extracts from the log file:_*
> 
> INFO   | jvm 1    | 2010/11/02 04:54:33 | Desired survivor size 13107200 
> bytes, new threshold 4 (max 4)
> 
> INFO   | jvm 1    | 2010/11/02 04:54:33 | - age   1:     544000 
> bytes,     544000 total
> 
> INFO   | jvm 1    | 2010/11/02 04:54:33 | - age   2:     346320 
> bytes,     890320 total
> 
> INFO   | jvm 1    | 2010/11/02 04:54:33 | - age   3:     262800 
> bytes,    1153120 total
> 
> INFO   | jvm 1    | 2010/11/02 04:54:33 | - age   4:     238528 
> bytes,    1391648 total
> 
> INFO   | jvm 1    | 2010/11/02 04:54:33 | : 155621K->2065K(179200K), 
> 0.1046330 secs] 988712K->835373K(1022976K) icms_dc=0 , 0.1047500 secs] 
> [Times: user=0.00 sys=0.00, real=0.11 secs]
> 
> INFO   | jvm 1    | 2010/11/02 04:55:54 | 422097.583: [GC 422097.583: 
> [ParNew
> 
> INFO   | jvm 1    | 2010/11/02 04:55:54 |
> 
> INFO   | jvm 1    | 2010/11/02 04:55:54 | Desired survivor size 13107200 
> bytes, new threshold 4 (max 4)
> 
> INFO   | jvm 1    | 2010/11/02 04:55:54 | - age   1:     577104 
> bytes,     577104 total
> 
> INFO   | jvm 1    | 2010/11/02 04:55:54 | - age   2:     261856 
> bytes,     838960 total
> 
> INFO   | jvm 1    | 2010/11/02 04:55:54 | - age   3:     298832 
> bytes,    1137792 total
> 
> INFO   | jvm 1    | 2010/11/02 04:55:54 | - age   4:     259176 
> bytes,    1396968 total
> 
> INFO   | jvm 1    | 2010/11/02 04:55:54 | : 155664K->2386K(179200K), 
> 0.0498010 secs] 988972K->835920K(1022976K) icms_dc=0 , 0.0499370 secs] 
> [Times: user=0.00 sys=0.00, real=0.05 secs]
> 
> INFO   | jvm 1    | 2010/11/02 04:57:27 | 422190.993: [GC 422190.993: 
> [ParNew
> 
> INFO   | jvm 1    | 2010/11/02 04:57:28 |
> 
> INFO   | jvm 1    | 2010/11/02 04:57:28 | Desired survivor size 13107200 
> bytes, new threshold 4 (max 4)
> 
> INFO   | jvm 1    | 2010/11/02 04:57:28 | - age   1:     676656 
> bytes,     676656 total
> 
> INFO   | jvm 1    | 2010/11/02 04:57:28 | - age   2:     283376 
> bytes,     960032 total
> 
> INFO   | jvm 1    | 2010/11/02 04:57:28 | - age   3:     239472 
> bytes,    1199504 total
> 
> INFO   | jvm 1    | 2010/11/02 04:57:28 | - age   4:     264960 
> bytes,    1464464 total
> 
> INFO   | jvm 1    | 2010/11/02 04:57:28 | : 155986K->1918K(179200K), 
> 0.0652010 secs] 989520K->835699K(1022976K) icms_dc=0 , 0.0653200 secs] 
> [Times: user=0.01 sys=0.00, real=0.07 secs]
> 
> INFO   | jvm 1    | 2010/11/02 04:58:54 | 422277.406: [GC 422277.406: 
> [ParNew
> 
> INFO   | jvm 1    | 2010/11/02 04:58:54 | Desired survivor size 13107200 
> bytes, new threshold 4 (max 4)
> 
> INFO   | jvm 1    | 2010/11/02 04:58:54 | - age   1:     615944 
> bytes,     615944 total
> 
> INFO   | jvm 1    | 2010/11/02 04:58:54 | - age   2:     334120 
> bytes,     950064 total
> 
> INFO   | jvm 1    | 2010/11/02 04:58:54 | - age   3:     276736 
> bytes,    1226800 total
> 
> INFO   | jvm 1    | 2010/11/02 04:58:54 | - age   4:     236424 
> bytes,    1463224 total
> 
> INFO   | jvm 1    | 2010/11/02 04:58:54 | : 155518K->1928K(179200K), 
> 0.0378730 secs] 989299K->835959K(1022976K) icms_dc=0 , 0.0379920 secs] 
> [Times: user=0.00 sys=0.00, real=0.04 secs]
> 
> INFO   | jvm 1    | 2010/11/02 05:00:23 | 422366.439: [GC 422366.439: 
> [ParNew
> 
> INFO   | jvm 1    | 2010/11/02 05:00:23 |  (promotion failed)
> 
> INFO   | jvm 1    | 2010/11/02 05:00:23 | Desired survivor size 13107200 
> bytes, new threshold 4 (max 4)
> 
> INFO   | jvm 1    | 2010/11/02 05:00:23 | - age   1:     574000 
> bytes,     574000 total
> 
> INFO   | jvm 1    | 2010/11/02 05:00:23 | - age   2:     315432 
> bytes,     889432 total
> 
> INFO   | jvm 1    | 2010/11/02 05:00:23 | - age   3:     281216 
> bytes,    1170648 total
> 
> INFO   | jvm 1    | 2010/11/02 05:00:23 | - age   4:     271776 
> bytes,    1442424 total
> 
> INFO   | jvm 1    | 2010/11/02 05:00:23 | : 155528K->155689K(179200K), 
> 0.1007840 secs]422366.540: [CMS
> 
> INFO   | jvm 1    | 2010/11/02 05:01:46 | [Unloading class 
> sun.reflect.GeneratedMethodAccessor121]
> 
> INFO   | jvm 1    | 2010/11/02 05:01:46 | [Unloading class 
> sun.reflect.GeneratedMethodAccessor119]
> 
> INFO   | jvm 1    | 2010/11/02 05:01:46 | [Unloading class 
> sun.reflect.GeneratedMethodAccessor124]
> 
> INFO   | jvm 1    | 2010/11/02 05:01:46 | [Unloading class 
> sun.reflect.GeneratedMethodAccessor123]
> 
> INFO   | jvm 1    | 2010/11/02 05:01:46 | [Unloading class 
> sun.reflect.GeneratedMethodAccessor120]
> 
> INFO   | jvm 1    | 2010/11/02 05:01:46 | [Unloading class 
> sun.reflect.GeneratedMethodAccessor122]
> 
> ERROR  | wrapper  | 2010/11/02 05:02:37 | JVM appears hung: Timed out 
> waiting for signal from JVM.
> 
>  
> 
>  
> 
> *Dori Rabin*
> 
> *cid:image001.gif at 01CB69E7.E5E45760*
> 
>  
> 
> *cid:image002.jpg at 01CB69E7.E5E45760*
> 
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> 
> Email: mailto:Dori <mailto:your-email-address>.Rabin at starhome.com
> 
>  
> 
>  
> 
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