why doesn't trigger compile when loop 10700 times?

[Kirk Pepperdine]

Hi, 

I believe with loops you should see an OSR but only after a count of 14000. I don’t believe this will be precise though.

Kind regards,
Kirk Pepperdine

On Jun 28, 2015, at 6:36 AM, Vladimir Kozlov <vladimir.kozlov at oracle.com> wrote:

> Add -Xbatch (or -XX:-BackgroundCompilation) otherwise code continue execution after requesting compilation and may finish before compilation starts.
> Also counters are not precise so you may not see exact 10700.
> 
> Regards,
> Vladimir
> 
> On 6/27/15 9:15 PM, weatry at gmail.com wrote:
>> 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