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1. Re: High CPU consumption.
peterj Mar 3, 2007 5:24 PM (in response to jpicard)The best thing to do is take some thread dumps when you see the unexpected processor usage. Those should tell you what is running.
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2. Re: High CPU consumption.
lafr Mar 4, 2007 5:11 PM (in response to jpicard)Execute "jmap -heap " to see the memory use.
If the memory use reaches 100% the server is constantly running garbage collections which consume many CPU cycles.
Perhaps you'll have to adjust the memory settings on startup. -
3. Re: High CPU consumption.
jpicard Mar 5, 2007 3:12 AM (in response to jpicard)Hello,
Thanks for your help.
Here is a result of the command 'jmap -heap', could you help me to interpret this result, and to optimize my parameters?
Best Regards,
Jerome.
Attaching to process ID 11776, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 1.5.0_11-b03
using parallel threads in the new generation.
using thread-local object allocation.
Mark Sweep Compact GC
Heap Configuration:
MinHeapFreeRatio = 40
MaxHeapFreeRatio = 70
MaxHeapSize = 2147483648 (2048.0MB)
NewSize = 2686976 (2.5625MB)
MaxNewSize = -65536 (-0.0625MB)
OldSize = 1835008 (1.75MB)
NewRatio = 2
SurvivorRatio = 8
PermSize = 21757952 (20.75MB)
MaxPermSize = 134217728 (128.0MB)
Heap Usage:
New Generation (Eden + 1 Survivor Space):
capacity = 644218880 (614.375MB)
used = 581578344 (554.6363296508789MB)
free = 62640536 (59.738670349121094MB)
90.27651347318476% used
Eden Space:
capacity = 572653568 (546.125MB)
used = 572344744 (545.8304824829102MB)
free = 308824 (0.29451751708984375MB)
99.94607140909318% used
From Space:
capacity = 71565312 (68.25MB)
used = 9233600 (8.80584716796875MB)
free = 62331712 (59.44415283203125MB)
12.902340172847985% used
To Space:
capacity = 71565312 (68.25MB)
used = 0 (0.0MB)
free = 71565312 (68.25MB)
0.0% used
tenured generation:
capacity = 1431699456 (1365.375MB)
used = 254001848 (242.23503875732422MB)
free = 1177697608 (1123.1399612426758MB)
17.741282706752667% used
Perm Generation:
capacity = 80216064 (76.5MB)
used = 80136544 (76.42416381835938MB)
free = 79520 (0.075836181640625MB)
99.90086773641748% used -
4. Re: High CPU consumption.
lafr Mar 11, 2007 7:04 PM (in response to jpicard)You set the MaxPermSize but not the starting value: add "-XX:NewSize=128m" to the parameter list.
Don't know much about the flags "-XX:+UseParNewGC" and "-XX:+CMSParallelRemarkEnabled" and JBoss on Linux, but I would try to run without it.
JDK 1.5 checks the system for available CPUs and memory and set's values based on that.
You also may add "-verbose:gc -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:-TraceClassUnloading" to see GC messages and see if there are messages generated constantly when the CPU load increases.