jvm优化

<jvm-arg>-server</jvm-arg>
 <jvm-arg>-Xms1524M</jvm-arg>

 <jvm-arg>-Xmx1524M</jvm-arg>

 <jvm-arg>-Xmn512M</jvm-arg>
 <jvm-arg>-Xss1M</jvm-arg>
 

 <jvm-arg>-XX:PermSize=256M</jvm-arg>

 <jvm-arg>-XX:MaxPermSize=256M</jvm-arg>

 <jvm-arg>-XX:SurvivorRatio=8</jvm-arg>

 <jvm-arg>-XX:MaxTenuringThreshold=7</jvm-arg>

 <jvm-arg>-XX:GCTimeRatio=19</jvm-arg>

 <jvm-arg>-XX:+UseParNewGC</jvm-arg>

 <jvm-arg>-XX:+UseConcMarkSweepGC</jvm-arg>
 <jvm-arg>-XX:+CMSPermGenSweepingEnabled</jvm-arg>
 <jvm-arg>-XX:+CMSClassUnloadingEnabled</jvm-arg>

 <jvm-arg>-XX:+UseCMSCompactAtFullCollection</jvm-arg>

 <jvm-arg>-XX:CMSFullGCsBeforeCompaction=2</jvm-arg>
 <jvm-arg>-XX:-CMSParallelRemarkEnabled</jvm-arg>
 <jvm-arg>-XX:+DisableExplicitGC</jvm-arg>

 <jvm-arg>-XX:CMSInitiatingOccupancyFraction=70</jvm-arg>

 <jvm-arg>-XX:SoftRefLRUPolicyMSPerMB=0</jvm-arg>
 

 <jvm-arg>-XX:+PrintClassHistogram</jvm-arg>

 <jvm-arg>-XX:+PrintGCDetails</jvm-arg>

 <jvm-arg>-XX:+PrintGCTimeStamps</jvm-arg>

 <jvm-arg>-XX:+PrintGCApplicationConcurrentTime</jvm-arg>

 <jvm-arg>-XX:+PrintGCApplicationStoppedTime</jvm-arg> 

 <jvm-arg>-Xloggc:log/gc.log</jvm-arg>