initialization times for invokedynamic

[Jochen Theodorou]

Hi,

I write myself a small microbenchmark to get an idea about the time it
takes to initialize a callsite. I made a simple test in which I write a
class with a run method, which calls a method foo(I)I using
invokedynamic and all the bootstrap method does is

> handle = caller.findStatic(IndyCallsiteTests.class, name, type);
> return new ConstantCallSite(handle);

I compared this with a simple reflective solution:

>         Runnable r = new Runnable() {
>             @Override
>             public void run() {
>                Method m = IndyCallsiteTests.class.getMethod("foo", int.class);
>                m.invoke(null, 1);
>             }
>         };

and one with a very simple reflective caching:

>         Runnable r = new Runnable() {
>             Method m = null;
>             @Override
>             public void run() {
>                 if (m == null) {
>                     m = IndyCallsiteTests.class.getMethod("foo", int.class);
>                 }
>                 m.invoke(null, 1);
>             }
>         };

And my findings are that of course indy performs best in the long term,
but based on reports I was wondering more about the initial costs. For
the first couple of calls I get

reflectiveCallCached
------------------------------------
52627
8861
4335
3472
6032
6209
7484
7406
7267
6945
7546
7321

In sum ~122_000

reflectiveCall
------------------------------------
61720
20147
4916
3719
4723
3421
4839
4661
5428
4379
4615
4453

In sum ~127_000

indyCall
------------------------------------
835411
1461
1229
1335
1257
1500
1154
1546
1423
1351
1318
1303

In sum ~850_000

While peak performance is much better with indy, it takes a lot of calls
(100k-200k) in this scenario for the indyCall to catch up to the other
two variants.

I would like to know if others on this list have similar experiences. Or
did I make a fundamental mistake?

bye Jochen