Remi, thanks for the report!
Filed JDK-8072008 [1].
Best regards,
Vladimir Ivanov
[1] https://bugs.openjdk.java.net/browse/JDK-8072008
On 1/30/15 4:03 AM, Remi Forax wrote:
On 01/30/2015 01:48 AM, John Rose wrote:
On Jan 7, 2015, at 8:13 AM, Remi Forax <fo...@univ-mlv.fr
<mailto:fo...@univ-mlv.fr>> wrote:
But if fibo is called through an invokedynamic, instead of emitting a
direct call to fibo,
the JIT generates a code that push the method handle on stack and
execute it
like if the metod handle was not constant
(the method handle is constant because the call at depth=1 is inlined !).
Invocation of non-constant MH's had a performance regression with the
LF-based implementation.
As of JDK-8069591 they should be no slower and sometimes faster than
the old implementation.
— John
In my case, the method handle is constant (I think it's also the case
when you write fibo in javascript).
At depth=1, the call is correctly inlined.
At depth=2, the call is not inlined because it's a recursive call and by
default hotspot only inline recursive call once,
this is normal behavior. The bug is that instead of doing a call (using
the call assembly instruction),
the JIT pushes the method handle on stack and do an invokebasic, which
is slower.
Rémi
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