Is there a way to trigger JIT manually other than java.lang.Compiler

Question

I'm trying to build a JIT strategy based on method structure with profiling info (provided by JVM) but i didn't able to trigger JIT manually. This documentation says i can run JIT by invoking java.lang.Compiler.compileClass() but method returns false every time and the property that java.lang.Compiler checks (java.compiler) is null every time i run the JVM. I tried on OpenJDK and Oracle JVM 1.7 both results the same.

However when i observe the compilation statistics with

$ jstat -printcompilation <PID>

I can see the JIT successfully compiles some method which fits the conditions.

If any way exist I rather trigger it from java code. I tried to search in hotspot VM's code too but I couldn't locate the class and method where the decision made and JIT start.

Edit: After looking around more I found the compilationPolicy.cpp bu still couldn't find the exact location that the decision depend on. I would expect something like (simply thinking)

if(hot_count > Threshold){
   compile_method(methodHandle);
}

but instead found this,

void SimpleCompPolicy::method_invocation_event(methodHandle m, JavaThread* thread) {
const int comp_level = CompLevel_highest_tier;
  const int hot_count = m->invocation_count();
  reset_counter_for_invocation_event(m);
  const char* comment = "count";

  if (is_compilation_enabled() && can_be_compiled(m)) {
    nmethod* nm = m->code();
    if (nm == NULL ) {
    // [MY COMMENT] no check being done on hot_count in here or callee methods
      CompileBroker::compile_method(m, InvocationEntryBci, comp_level, m, hot_count, comment, thread);
    }
  }
}

As far as tracing the native JVM code, im getting away my main topic. Still looking for a simple solution to use in java side of the code.

Answer 1

It sounds like you want something similar to the Compiler Control feature (http://openjdk.java.net/jeps/165).

Unfortunately, it doesn't exist yet, although it is currently scheduled to form part of Java 9.