why doesn't trigger compile when loop 10700 times?

[weatry at gmail.com]

hi, everyone! 

    I have some question about the jdk 1.7 compiler.

    According to the source code of "hotspot\src\share\vm\interpreter\invocationCounter.cpp", the "InterpreterBackwardBranchLimit" is calculated by the following rules:

  if (ProfileInterpreter) {
    InterpreterBackwardBranchLimit = (CompileThreshold * (OnStackReplacePercentage - InterpreterProfilePercentage)) / 100;
  } else {
    InterpreterBackwardBranchLimit = ((CompileThreshold * OnStackReplacePercentage) / 100) << number_of_noncount_bits;
  }

    So if I run a piece of code on a server edition jvm, the InterpreterBackwardBranchLimit should be 10700 (CompileThreshold is 10000, OnStackReplacePercentage is 140, and InterpreterProfilePercentage is 33). But when I added -XX:+PrintCompilation,  a loop with 10700 times would not print anything. When the loop growed up to 14564 times, the compiler began to work.

    Could anybody give me some advice?

    I use jdk1.7.0_67, and the test code as following:

public class OSRDemo {
public static void main(String[] args) {
int result = 1;
for (int i = 1; i < 10700; i++) {//14564
result+=i;
}

System.out.println(result);
}
}

    Thank you very much!



Thomas
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