Metronome Garbage Collector options

The definitions of the Metronome Garbage Collector options.

-Xgc:synchronousGCOnOOM | -Xgc:nosynchronousGCOnOOM
One occasion when garbage collection occurs is when the heap runs out of memory. If there is no more free space in the heap, using -Xgc:synchronousGCOnOOM stops your application while garbage collection removes unused objects. If free space runs out again, consider decreasing the target utilization to allow garbage collection more time to complete. Setting -Xgc:nosynchronousGCOnOOM implies that when heap memory is full your application stops and issues an out-of-memory message. The default is -Xgc:synchronousGCOnOOM.
-Xnoclassgc
Disables class garbage collection. This option switches off garbage collection of storage associated with Java™ classes that are no longer being used by the JVM. The default behavior is -Xnoclassgc.
-Xgc:targetUtilization=N
Sets the application utilization to N%; the Garbage Collector attempts to use at most (100-N)% of each time interval. Reasonable values are in the range of 50-80%. Applications with low allocation rates might be able to run at 90%. The default is 70%.
This example shows the maximum size of the heap memory is 30 MB. The garbage collector attempts to use 25% of each time interval because the target utilization for the application is 75%.
java -Xgcpolicy:metronome -Xmx30m -Xgc:targetUtilization=75 Test 
-Xgc:threads=N
Specifies the number of GC threads to run. The default is the number of processor cores available to the process. The maximum value you can specify is the number of processors available to the operating system.
-Xgc:verboseGCCycleTime=N
N is the time in milliseconds that the summaries should be dumped.
Note: The cycle time does not mean that the summary is dumped precisely at that time, but rather when the last GC quanta or heartbeat that passes this time criteria.
-Xmx<size>
Specifies the Java heap size. Unlike other garbage collection strategies, the real-time Metronome GC does not support heap expansion. There is not an initial or maximum heap size option. You can specify only the maximum heap size.


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