A Slow Yong GC question

[Srinivas Ramakrishna]

Monitor your paging rate; perhaps there are other processes on the system
that are causing the young gen and parts of the old gen to page?

You might also try -XX:+AlwaysPreTouch in case this happens when the
application footprint is growing and physical pages are allocated
for the first time. (That would typically show up as a more-or-less
periodic increase in scavenge pauses as we cross into new physical pages in
the old gen.)

-- ramki


On Sun, Dec 9, 2012 at 1:23 AM, 于凤东 <azuryy_yu at 126.com> wrote:

>  hi,
> I found sometimes yong gc is very slow, it paused more than 10 seconds.
> GC log:
> 1383.531: [GC 1383.531: [ParNew: 235968K->26176K(235968K), 14.1752210
> secs] 1518208K->1356662K(4168128K), 14.6084490 secs] [Times: user=9.77
> sys=0.14, real=14.61 secs]
> Total time for which application threads were stopped: 14.6241190 seconds
>
> jstat : (jstat -gc -h 10 20010 1000)
>
>           S0C    S1C    S0U    S1U      EC       EU        OC
> OU       PC     PU    YGC     YGCT    FGC    FGCT     GCT
>           26176.0 26176.0 26176.0 26176.0 209792.0 209792.0 3932160.0
> 1315008.8  163840.0 22007.9    434  330.795  14      3.943  334.738
>          26176.0 26176.0 26176.0 26176.0 209792.0 209792.0 3932160.0
> 1315008.8  163840.0 22007.9    434  330.795  14      3.943  334.738
>          26176.0 26176.0 26176.0  0.0   209792.0   0.0    3932160.0
> 1330486.2  163840.0 22007.9    434  344.970  14      3.943  348.913
>
> Eden, S0, S1 are all full, then yong gc paused more than 14 seconds. any
> body give me some advice, appreciate much.
>
> 1) I used:
> java version "1.7.0_09"
> Java(TM) SE Runtime Environment (build 1.7.0_09-b05)
> Java HotSpot(TM) 64-Bit Server VM (build 23.5-b02, mixed mode)
>
> 2) My JVM options as follow(yong objects have a short life generally, so
> -Xmn256m):
> -Xmx4g -Xms4g -Xmn256m  -server -verbose:gc -XX:+PrintGCTimeStamps
> -XX:+PrintGCDetails -XX:+PrintGCApplicationStoppedTime
> -XX:-HeapDumpOnOutOfMemoryError -XX:+UseGCLogFileRotation
> -XX:NumberOfGCLogFiles=9 -XX:GCLogFileSize=20m -XX:+DisableExplicitGC
> -XX:+UseCompressedOops -XX:PermSize=160m -XX:MaxPermSize=160m
> -XX:GCTimeRatio=19 -XX:SoftRefLRUPolicyMSPerMB=0 -XX:SurvivorRatio=8
> -XX:MaxTenuringThreshold=6 -XX:+UseParNewGC -XX:+UseConcMarkSweepGC
> -XX:+CMSParallelRemarkEnabled -XX:CMSInitiatingOccupancyFraction=70
> -XX:+UseCMSCompactAtFullCollection -XX:CMSFullGCsBeforeCompaction=0
> -XX:+CMSClassUnloadingEnabled -XX:CMSMaxAbortablePrecleanTime=300
> -XX:+CMSScavengeBeforeRemark
> -XX:ErrorFile=/usr/local/hase/logs/rs_error_gc.log
> -Xloggc:/usr/local/hbase/logs/rs_gc.log
> -XX:HeapDumpPath=/usr/local/hbase/logs/rs_error.hprof
>
>
>
>
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>
>
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