CODEWITHSUNDEEP
javajvmjitjstat
user12730122
user12730122

Reputation: 37

How to understand jstat -printcompilation output

jstat -printcompilation pid

can get information about the last method that is compiled, like:

Compiled  Size  Type Method
     207     64    1 java/lang/CharacterDataLatin1 toUpperCase
     208      5    1 java/math/BigDecimal$StringBuilderHelper getCharArray

What's the third column mean? I can't find detail info about 'Type'. How many types inclued?

https://docs.oracle.com/javase/9/tools/jstat.htm#JSWOR734

oracle document dont' have enough info yet

Upvotes: 1

Views: 541

Answers (1)

apangin
apangin

Reputation: 98304

The value in Type column corresponds to this enum:

1 = normal_compile  // Regular JIT compilation
2 = osr_compile     // On-stack replacement
3 = native_compile  // Compiled wrapper for a native method

However, the values other than normal_compile are available only in debug builds of the JVM when -XX:+CICountOSR or -XX:+CICountNative option is set:

  int last_compile_type = normal_compile;
  if (CICountOSR && is_osr) {
    last_compile_type = osr_compile;
  } else if (CICountNative && method->is_native()) {
    last_compile_type = native_compile;
  }

In practice this means that Type is always 1 with a regular JDK.

Upvotes: 1

Related Questions