??????????? - Java SE Embedded 8
- by kshimizu-Oracle
Java?OS??????1?????????????????????????????????3??????????????
HEAP: Java?????????????????????????????????
NON-HEAP: NON-HEAP????JVM???????????????????Code Cache?Metaspace???2?????????????
Code Cache: ????JIT???????????????????????????
Metaspace: HEAP??????????????????????????
JavaVM??????????: VM??????????????????
???????????????
?????????????????????????????????????????????????????????????????????????
HEAP?Java Mission Control???????????????????? (????)? ????Java SE?????????????API????????????????????????????????????? Mission Control?????API?????????????????????????????????API???????????????
HEAP???????????? VM????????"-Xmx"????????????????
java.lang.Runtime.maxMemory();
?????HEAP????????? ?????VM????????"-Xms"? ????????????? "-Xms"???????"-Xmx"??????????
java.lang.Runtime.totalMemory();
???????????HEAP????????????? java.lang.Runtime.freeMemory();
??NON-HEAP???????????? API??????????? Java Mission Control?????????? ????????????Java Mission Control??????????????????????? ????"NON_HEAP"?????????NON-HEAP??????
???? HEAP????NON-HEAP?????????????? Java VM???????????????????????????????????????? ?????????????????????????????????? ????HEAP/NON-HEAP?????????????????????????? OS?????????????? Linux???????procfs?Java??????????????????? (VmHWM or VmRSS) ????? ????HEAP/NON-HEAP???????????????????????????
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??????JVM?????????????????? ?????????????????JVM???????????????????? ???JVM??????
????????????? Embedded??JVM?????????? ??Embedded???Oracle JVM??????CPU????????????????????????????????????????? ??????CPU???????????????????????????????????????
Minimal/Client/Server??JVM???????????????? ????JVM???????????????????
??????Compact?????????????????
? 2 - 3?????? Concept Guide (http://docs.oracle.com/javase/8/embedded/embedded-concepts/basic-concepts.htm) ????????
??JVM??????????? ?????????????????????
-Xms: ??????????? ?????????? ??????????????????????????????????????????????????
-Xmx: ???????????
-XX:ReservedCodeCacheSize: Code Cache??????? ?) JIT??????????????Code Cache????????????0????????
-Xint: JIT??????????? ????????????? JIT?????????????????????? ?????????????????
-Xss: ???????????????????? ????????????????????????? ?????????????????????????????
-XX:CompileThreshold: JIT?????????????????????????????????? ?????????????????????? ????????? ?????????????????? Code Cache??????????
?????????? ????????????????????? ????????????????????????? ??????????????????????? ?????????????????????