Changes between Version 9 and Version 10 of manuals/jvm-tunning


Ignore:
Timestamp:
07/07/10 13:27:58 (10 years ago)
Author:
tigran
Comment:

--

Legend:

Unmodified
Added
Removed
Modified
  • manuals/jvm-tunning

    v9 v10  
    1414}}} 
    1515 
    16 '''Setting Heap Size'''  
     16'''Setting Heap Size''' 
    1717 
    18 A number of parameters affect generation size.. At initialization of the virtual machine, the entire space for the heap is reserved. Thesize of the space reserved can be specified with the -Xmxoption. If thevalue of the -Xmsparameter is smaller than the value of the-Xmxparameter, not all of the space that is reserved is immediately committed to the virtual machine. It is recommended to set -Xms and -Xmx to the same value. Setting -Xms and -Xmx to the same value increases predictability by removing the most important sizing decision from the virtual machine. 
     18A number of parameters affect generation size.. At initialization of the virtual machine, the entire space for the heap is reserved. The size of the space reserved can be specified with the -Xmx option. If the value of the -Xms parameter is smaller than the value of the -Xmx parameter, not all of the space that is reserved is immediately committed to the virtual machine. It is recommended to set -Xms and -Xmx to the same value. Setting -Xms and -Xmx to the same value increases predictability by removing the most important sizing decision from the virtual machine. 
    1919 
    2020For example: 
     
    3838For example, to size a 128 MB young generation with an Eden of 64MB, a Survivor-Space size of 32MB, the !NewSize, !MaxNewSize, and !SurvivorRatiovalues can be specified as follows: 
    3939 
    40 java -Xms512m -Xmx512m -'''XX:NewSize=128m -XX:MaxNewSize=128m'''  
     40java -Xms512m -Xmx512m '''-XX:NewSize=128m -XX:MaxNewSize=128m'''  
    4141    -XX:SurvivorRatio=2 application 
    4242 
     
    4646The old generation or the tenured generation is used to hold orage objects promoted from the younger generation. The maximum size of the older generation is controlled by the -Xms parameter. 
    4747 
    48 For the previous example to size a 256 MB old generation heap with a young generation of 256 MB the -mx value can be specified as: 
     48For the previous example to size a 256 MB old generation heap with a young generation of 256 MB the -Xmx value can be specified as: 
    4949 
    5050 
     
    117117 
    118118{{{ 
    119 -XX:+UseParNewGC -XX:+UseConcMarkSweepGC-XX:MaxTenuringThreshold=0  
    120        -XX:SurvivorRatio=20000-XX:CMSInitiatingOccupancyFraction=60-XX:+UseCMSInitiatingOccupancyOnly  
    121        -XX:+CMSParallelRemarkEnabled-XX:+DisableExplicitGC 
     119-XX:+UseParNewGC -XX:+UseConcMarkSweepGC -XX:MaxTenuringThreshold=0  
     120       -XX:SurvivorRatio=20000 -XX:CMSInitiatingOccupancyFraction=60 -XX:+UseCMSInitiatingOccupancyOnly  
     121       -XX:+CMSParallelRemarkEnabled -XX:+DisableExplicitGC 
    122122}}} 
    123123