speed of invokeExact

[Jochen Theodorou]

Am 10.05.2013 02:40, schrieb Christian Thalinger:
[...]
> That's because your method handle is not constant and so the compiler cannot inline the call.

If I change the test to (using 1.8.0):
>         Object[] os = {"str", 1, new ArrayList(), new Object()};
>         MethodType invokeType = MethodType.methodType(String.class, Object.class);
>         MethodHandle[] mhs = new MethodHandle[os.length];
>         for (int i=0; i<os.length; i++) {
>             MethodHandle mh = MethodHandles.lookup().findVirtual(os[i].getClass(), "toString", MethodType.methodType(String.class));
>             mhs[i] = mh.asType(invokeType);
>         }
>         int tmax = 1_000_000;
>         for (int k=0; k<20; k++) {
>             long t1 = System.nanoTime();
>             for (int i=0; i<tmax; i++) {
>                 for (int j=0; j<os.length; j++) {
>                     String s = (String) mhs[j].invokeExact(os[j]);
>                 }
>             }
>             long t2 = System.nanoTime();
>             System.out.println((t2-t1)/tmax/os.length);
>         }

then I doubt there is still any inlining happening. Here I get around 63 
(case1). Since I have some probably complex toString action in here I 
guess I cannot really compare that number with the test before. But it 
is still under those 800. If I pull the asType into the loop (case2) 
then I get something of 830-1000. And if I actually remove the 
invokeExact and leave only the asType in the loop (case3), I get 730-840

For jdk 1.7.11 I get in
case 1: 70-100
case 2: 380-480
case 3: 300-400

bye Jochen

-- 
Jochen "blackdrag" Theodorou - Groovy Project Tech Lead
blog: http://blackdragsview.blogspot.com/
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