Intermittent long ParNew times

[Erwin]

Hello,

When we’re running our load test for about 1 hour, GC seems to be fine most of the times. However, there are times where the ParNew would go as high as 25 seconds. See below sample where it was 10 seconds.
{Heap before GC invocations=11 (full 0):
 par new generation   total 921600K, used 880508K [0xfffffffdd0000000, 0xfffffffe0e800000, 0xfffffffe0e800000)
  eden space 819200K, 100% used [0xfffffffdd0000000, 0xfffffffe02000000, 0xfffffffe02000000)
  from space 102400K,  59% used [0xfffffffe08400000, 0xfffffffe0bfdf1c8, 0xfffffffe0e800000)
  to   space 102400K,   0% used [0xfffffffe02000000, 0xfffffffe02000000, 0xfffffffe08400000)
 concurrent mark-sweep generation total 3170304K, used 685978K [0xfffffffe0e800000, 0xfffffffed0000000, 0xffffffff48000000)
 concurrent-mark-sweep perm gen total 524288K, used 221175K [0xffffffff48000000, 0xffffffff68000000, 0xffffffff73800000)
37814.384: [GC 37814.384: [ParNew: 880508K->55794K(921600K), 0.1246958 secs] 1566486K->741772K(4091904K), 0.1249910 secs] [Times: user=0.37 sys=0.07, real=0.13 secs] 
Heap after GC invocations=12 (full 0):
 par new generation   total 921600K, used 55794K [0xfffffffdd0000000, 0xfffffffe0e800000, 0xfffffffe0e800000)
  eden space 819200K,   0% used [0xfffffffdd0000000, 0xfffffffdd0000000, 0xfffffffe02000000)
  from space 102400K,  54% used [0xfffffffe02000000, 0xfffffffe0567c880, 0xfffffffe08400000)
  to   space 102400K,   0% used [0xfffffffe08400000, 0xfffffffe08400000, 0xfffffffe0e800000)
 concurrent mark-sweep generation total 3170304K, used 685978K [0xfffffffe0e800000, 0xfffffffed0000000, 0xffffffff48000000)
 concurrent-mark-sweep perm gen total 524288K, used 221175K [0xffffffff48000000, 0xffffffff68000000, 0xffffffff73800000)

{Heap before GC invocations=12 (full 0):
 par new generation   total 921600K, used 874994K [0xfffffffdd0000000, 0xfffffffe0e800000, 0xfffffffe0e800000)
  eden space 819200K, 100% used [0xfffffffdd0000000, 0xfffffffe02000000, 0xfffffffe02000000)
  from space 102400K,  54% used [0xfffffffe02000000, 0xfffffffe0567c880, 0xfffffffe08400000)
  to   space 102400K,   0% used [0xfffffffe08400000, 0xfffffffe08400000, 0xfffffffe0e800000)
 concurrent mark-sweep generation total 3170304K, used 685978K [0xfffffffe0e800000, 0xfffffffed0000000, 0xffffffff48000000)
 concurrent-mark-sweep perm gen total 524288K, used 221531K [0xffffffff48000000, 0xffffffff68000000, 0xffffffff73800000)
39088.225: [GC 39088.225: [ParNew: 874994K->102400K(921600K), 10.0339890 secs] 1560972K->821401K(4091904K), 10.0346984 secs] [Times: user=5.40 sys=31.71, real=10.04 secs] 
Heap after GC invocations=13 (full 0):
 par new generation   total 921600K, used 102400K [0xfffffffdd0000000, 0xfffffffe0e800000, 0xfffffffe0e800000)
  eden space 819200K,   0% used [0xfffffffdd0000000, 0xfffffffdd0000000, 0xfffffffe02000000)
  from space 102400K, 100% used [0xfffffffe08400000, 0xfffffffe0e800000, 0xfffffffe0e800000)
  to   space 102400K,   0% used [0xfffffffe02000000, 0xfffffffe02000000, 0xfffffffe08400000)
 concurrent mark-sweep generation total 3170304K, used 719001K [0xfffffffe0e800000, 0xfffffffed0000000, 0xffffffff48000000)
 concurrent-mark-sweep perm gen total 524288K, used 221531K [0xffffffff48000000, 0xffffffff68000000, 0xffffffff73800000)

We’re on 64bit platform of WAS NDE 7.0.0.9 on Solaris10 platform. Our JVM args are:
-server -Xmn1000m -XX:PermSize=512m -XX:+UseConcMarkSweepGC -XX:+HeapDumpOnOutOfMemoryError -DUseSunHttpHandler=true -Djavax.xml.soap.MessageFactory=weblogic.xml.saaj.MessageFactoryImpl -Doracle.jdbc.V8Compatible=true -XX:CMSInitiatingOccupancyFraction=70 -XX:+CMSClassUnloadingEnabled -verbose:gc -XX:+PrintGCTimeStamps -XX:+PrintGCDetails -XX:-TraceClassUnloading -XX:+PrintGCApplicationStoppedTime -XX:+PrintHeapAtGC  -XX:MaxPermSize=694m -XX:+DisableExplicitGC -XX:+CMSParallelRemarkEnabled

Any help would be appreciated.
Erwin