對 JRockit JVM優化
Task
|
Options
|
Comments
|
| Setting the Nursery
|
-Xns |
盡力使Nursery最夠大，來減少GC停頓時間。最大最好不要超過最大Heap 95%。
|
| Setting minimum heap size
|
-Xms |
BEA 推薦這個值最好等于最大的heap。
|
| Setting maximum heap size
|
-Xmx |
Heap最大值，當然越大越好。
|
| Setting garbage collection
|
-Xgc: parallel |
|
| Performs adaptive optimizations as early as possible in the Java application run. |
-XXaggressive:memory |
|
For example
$ java -Xns10m -Xms512m -Xmx512m
對 SUN JVM優化
| Task |
Options |
Comments
|
| Setting the New generation heap size
|
-XX:NewSize |
默認 NewSize大小是Heap的四分之一，類似Nursery，盡量設置大點減少GC停頓時間。
|
| Setting the maximum New generation heap size
|
-XX:MaxNewSize |
設置 New Generation heap 最大值.
|
| Setting New heap size ratios
|
-XX:SurvivorRatio |
在Sun generation分為3個區域，一個Edgn和兩個survivors。該值是設置Edgn與Surviors的比例。最好設置為8.
|
| Setting minimum heap size
|
-Xms |
推薦這個值最好等于最大的heap。 |
| Setting Big Heaps and Intimate Shared Memory
|
-XX:+UseISM -XX:+AggressiveHeap |
See http://java.sun.com/docs/hotspot/ism.html |
| Setting maximum heap size
|
-Xmx |
Heap最大值，當然越大越好。 |
For example,
$ java -XX:NewSize=128m -XX:MaxNewSize=128m -XX:SurvivorRatio=8 -Xms512m -Xmx512m