1. 查看程序的jvm启动参数
jcmd 106179 VM.flags
-XX:CICompilerCount=3 -XX:CMSInitiatingOccupancyFraction=80 -XX:+DisableExplicitGC -XX:ErrorFile=/opt/logs/com.sankuai.mall.promotion.operation/operation.hs_err_%p.log -XX:GCLogFileSize=536870912 -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/opt/logs/com.sankuai.mall.promotion.operation/operation.heap_err_%p.hprof -XX:InitialCodeCacheSize=134217728 -XX:InitialHeapSize=536870912 -XX:MaxHeapSize=536870912 -XX:MaxMetaspaceSize=268435456 -XX:MaxNewSize=178913280 -XX:MetaspaceSize=268435456 -XX:MinHeapDeltaBytes=196608 -XX:NewRatio=2 -XX:NewSize=178913280 -XX:NumberOfGCLogFiles=5 -XX:OldPLABSize=16 -XX:OldSize=357957632 -XX:+PrintGC -XX:+PrintGCDateStamps -XX:+PrintGCDetails -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC -XX:+PrintTenuringDistribution -XX:ReservedCodeCacheSize=134217728 -XX:SurvivorRatio=8 -XX:+UseCompressedClassPointers -XX:+UseCompressedOops -XX:+UseConcMarkSweepGC -XX:+UseFastUnorderedTimeStamps -XX:+UseGCLogFileRotation -XX:+UseParNewGC
2. 查看java相关程序,先切换到root或对应的用户下
jps
3. 查看gc 实时状态
jstat -gcutil 106179 5000 10
pid 106179 每5s打印一次,打印10次
4. 查看实时内存信息
/usr/local/java8/bin/jmap -heap 106179
5. 排查cpu使用问题
https://www.cnblogs.com/tankaixiong/p/5984023.html
https://www.cnblogs.com/liusxg/p/5811085.html