Amit,
Which jdk version are you using?
You give MaxGCPauseMillis=500, but it seems g1 is adjusting eden size
too big, up to 13g. I am curious why. Can you add a flag
-XX:+PrintAdaptiveSizePolicy? Meanwhile, to reduce young gc pause, can
you try to a smaller number for MaxGCPauseMillis, or give a smaller eden
size?
Another thing I noticed, whenever you have long gc pause, the system cpu
is high. Maybe the system is busy doing something else?
Thanks,
Jenny
On 1/21/2016 4:30 AM, Amit Mishra wrote:
Hello team,
Please help me with G1 GC long young generation pause..
At one of our Customer deployment we were using CMS with 48G heap size
and facing Concurrent mode failure every month.
To solve this we started load test using G1 GC on lab but we are
seeing intermittent long GC pause as long as 148 seconds,
Could you please look into logs and confirm what best we can do to
ascertain root cause and possible tuning to fix this.
Thanks for help in advance.
We are using default GC parameters:(Attaching full GC file as well)
JVM_ARGS="${JVM_ARGS} -XX:-OmitStackTraceInFastThrow"
JVM_ARGS="${JVM_ARGS} -XX:-UseSSE42Intrinsics"
JVM_ARGS="${JVM_ARGS} -XX:-ReduceInitialCardMarks"
JVM_ARGS="${JVM_ARGS} -XX:+UseG1GC"
JVM_ARGS="${JVM_ARGS} -XX:MaxGCPauseMillis=500"
JVM_ARGS="${JVM_ARGS} -XX:+UseCompressedOops"
JVM_ARGS="${JVM_ARGS} -XX:+PrintFlagsFinal"
JVM_ARGS="${JVM_ARGS} -XX:-EliminateLocks"
JVM_ARGS="${JVM_ARGS} -XX:+UseLargePages"
export GC_LOG="${PROJECT_HOME}/log/gcstats.log.$$"
JVM_ARGS=$JVM_ARGS" -Xloggc:${GC_LOG}"
JVM_ARGS=$JVM_ARGS" -verbose:gc"
JVM_ARGS="${JVM_ARGS} -XX:+DisableExplicitGC"
JVM_ARGS=$JVM_ARGS" -XX:+AggressiveOpts"
JVM_ARGS="${JVM_ARGS} -XX:+HeapDumpOnOutOfMemoryError"
JVM_ARGS="${JVM_ARGS} -XX:ReservedCodeCacheSize=128m"
JVM_ARGS="${JVM_ARGS} -XX:PermSize=256m"
JVM_ARGS="${JVM_ARGS} -XX:MaxPermSize=256m"
JVM_ARGS="${JVM_ARGS} -Xmx28672m"
JVM_ARGS="${JVM_ARGS} -Xms28672m
Long GC pause.
5020.853: [GC pause (young), 148.0343389 secs]
[Parallel Time: 142474.3 ms, GC Workers: 13]
[GC Worker Start (ms): Min: 5022695.7, Avg: 5022705.6, Max:
5022714.4, Diff: 18.7]
[Ext Root Scanning (ms): Min: 143.0, Avg: 2550.5, Max: 6442.5,
Diff: 6299.4, Sum: 33157.1]
[Update RS (ms): Min: 5704.6, Avg: 19017.1, Max: 45977.9, Diff:
40273.3, Sum: 247222.7]
[Processed Buffers: Min: 0, Avg: 26.9, Max: 291, Diff: 291,
Sum: 350]
[Scan RS (ms): Min: 70538.2, Avg: 92539.7, Max: 114688.0, Diff:
44149.8, Sum: 1203016.2]
[Object Copy (ms): Min: 894.7, Avg: 9265.9, Max: 20674.1, Diff:
19779.4, Sum: 120456.9]
[Termination (ms): Min: 10169.3, Avg: 19073.0, Max: 26684.1,
Diff: 16514.7, Sum: 247949.3]
[GC Worker Other (ms): Min: 0.1, Avg: 4.5, Max: 18.2, Diff:
18.0, Sum: 58.4]
[GC Worker Total (ms): Min: 142441.2, Avg: 142450.8, Max:
142461.1, Diff: 19.8, Sum: 1851860.7]
[GC Worker End (ms): Min: 5165155.6, Avg: 5165156.4, Max:
5165162.0, Diff: 6.4]
[Code Root Fixup: 2.2 ms]
[Clear CT: 11.2 ms]
[Other: 5546.7 ms]
[Choose CSet: 0.0 ms]
[Ref Proc: 47.4 ms]
[Ref Enq: 0.9 ms]
[Free CSet: 3642.1 ms]
[Eden: 13.2G(13.2G)->0.0B(1416.0M) Survivors: 16.0M->16.0M Heap:
24.7G(28.0G)->11.5G(28.0G)]
[Times: user=184.95 sys=34.49, real=148.07 secs]
Thanks,
Amit
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