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slow gc - t5240

2 replies [Last post]
robincusters
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Joined: 2008-01-11
Points: 0

Hello,

On a Sun T5240 I'm getting slow gc times and application response times:

Total time for which application threads were stopped: 2.5786450 seconds
Application time: 2.4526424 seconds
Total time for which application threads were stopped: 0.0064315 seconds
Application time: 112.1235999 seconds
1341.069: [GC 1341.100: [ParNew: 980650K->52426K(990336K), 9.8161469 secs] 980650K->52426K(2038912K), 9.8486632 secs]
Total time for which application threads were stopped: 9.8552564 seconds
Application time: 37.3051334 seconds
Total time for which application threads were stopped: 0.0674006 seconds
Application time: 175.5950045 seconds
2364.961: [GC 2364.961: [ParNew: 984522K->53213K(990336K), 3.8529870 secs] 984522K->53213K(2038912K), 3.8548209 secs]
Total time for which application threads were stopped: 3.9168607 seconds
Application time: 85.8567631 seconds

jdk 1.5.0_15-b04
Sun Application Server 8.1

jvm options:
-XX:LargePageSizeInBytes=256M
-XX:MaxPermSize=256M
-server
-Xmx1024m
-Xms1024m
-Xmn256m
-Xss128k
-XX:+AggressiveOpts
-XX:+DisableExplicitGC
-XX:ParallelGCThreads=8
-XX:+UseConcMarkSweepGC
-XX:+UseParNewGC
-XX:+AlwaysPreTouch
-XX:SurvivorRatio=8
-XX:TargetSurvivorRatio=90
-XX:MaxTenuringThreshold=15
-Dsun.rmi.dgc.client.gcInterval=990000
-Dsun.rmi.dgc.server.gcInterval=990000
-Xloggc:/var/tmp/gc-sjas-webidm-idm
-verbosegc
-XX:+PrintGCTimeStamps
-XX:+PrintGCDetails
-XX:+PrintGCApplicationConcurrentTime
-XX:+PrintGCApplicationStoppedTime

Any ideas on how to improve this?

TIA,
- Robin

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jmanuel_ll
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Joined: 2010-07-21
Points: 0

You may try to increase XX:ParallelGCThreads value. Can you run psrinfo -vp command an set gcthreads value equal to num of cpu's.

linuxhippy
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Joined: 2004-01-07
Points: 0

You could try a smaller young generation, e.g. with -XX:NewRatio=4 (or even 8, but I guess that will conflict with your 256mb page size, maybe 4mb would be a better choice).
This will lower your stop-the-world pauses at the expense of a bit of throughput.

- Clemens