On Jul 16, 2014, at 11:40 AM, Remi Forax <fo...@univ-mlv.fr> wrote:
>
> On 07/16/2014 07:38 PM, Vladimir Ivanov wrote:
>> Remi,
>>
>> The problem is that for every iteration you create new call site
>> > for(int i=0; i<100_000; i++) {
>> > new LoopyCS().getTarget().invokeExact(1_000);
>> > }
>>
>> In LoopyCS constructor you instantiates 3 new MethodHandles:
>> > target = MethodHandles.filterArguments(target, 0, FOO);
>> > target = MethodHandles.guardWithTest(ZERO,
>> > target,
>> > MethodHandles.dropArguments(MethodHandles.constant(int.class,
>> > 0).asType(MethodType.methodType(void.class)), 0, int.class));
>>
>> Since we don't cache LambdaForms yet for these combinators, 3 new
>> LambdaForms are created for each invocation. Then they are compiled to
>> bytecode and then JIT kicks in. That's why you see continuous JITing.
>>
>> If you reuse a call site object, it stabilizes very quickly.
>
> doh, sorry for this stupid code :(
Everyone makes mistakes once in a while. Even you, Remi ;-)
>
>>
>> Best regards,
>> Vladimir Ivanov
>
> Rémi
>
>>
>> On 7/12/14 6:05 PM, Remi Forax wrote:
>>> It seems that the JIT is lost with whe there is a loopy callsite and
>>> never stabilize (or the steady state is after the program ends).
>>>
>>> import java.lang.invoke.MethodHandle;
>>> import java.lang.invoke.MethodHandles;
>>> import java.lang.invoke.MethodType;
>>> import java.lang.invoke.MutableCallSite;
>>>
>>> public class Loop {
>>> static class LoopyCS extends MutableCallSite {
>>> public LoopyCS() {
>>> super(MethodType.methodType(void.class, int.class));
>>>
>>> MethodHandle target = dynamicInvoker();
>>> target = MethodHandles.filterArguments(target, 0, FOO);
>>> target = MethodHandles.guardWithTest(ZERO,
>>> target,
>>> MethodHandles.dropArguments(MethodHandles.constant(int.class,
>>> 0).asType(MethodType.methodType(void.class)), 0, int.class));
>>> setTarget(target);
>>> }
>>> }
>>>
>>> static final MethodHandle FOO, ZERO;
>>> static {
>>> try {
>>> FOO = MethodHandles.lookup().findStatic(Loop.class, "foo",
>>> MethodType.methodType(int.class, int.class));
>>> ZERO = MethodHandles.lookup().findStatic(Loop.class, "zero",
>>> MethodType.methodType(boolean.class, int.class));
>>> } catch (NoSuchMethodException | IllegalAccessException e) {
>>> throw new AssertionError(e);
>>> }
>>> }
>>>
>>> private static boolean zero(int i) {
>>> return i != 0;
>>> }
>>>
>>> private static int foo(int i) {
>>> COUNTER++;
>>> return i - 1;
>>> }
>>>
>>> private static int COUNTER = 0;
>>>
>>> public static void main(String[] args) throws Throwable {
>>> for(int i=0; i<100_000; i++) {
>>> new LoopyCS().getTarget().invokeExact(1_000);
>>> }
>>> System.out.println(COUNTER);
>>> }
>>> }
>>>
>>> cheers,
>>> Rémi
>>>
>>>
>>> _______________________________________________
>>> mlvm-dev mailing list
>>> mlvm-dev@openjdk.java.net
>>> http://mail.openjdk.java.net/mailman/listinfo/mlvm-dev
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