hotspot inlining decision seems to be random

[Ulf Zibis]

Please refer to:
[1]
https://java-nio-charset-enhanced.dev.java.net/source/browse/java-nio-charset-enhanced/branches/j7_EUC_TW/log/C_d_b_reverse1-2_highSurrogate_PA.xml?rev=866&view=markup
[2]
https://java-nio-charset-enhanced.dev.java.net/source/browse/java-nio-charset-enhanced/branches/j7_EUC_TW/log/C_d_b_reverse1-2_highSurrogate_PA_2.xml?rev=866&view=markup
[3] 
https://java-nio-charset-enhanced.dev.java.net/source/browse/java-nio-charset-enhanced/branches/j7_EUC_TW/log/C_d_b_reverse1-2_highSurrogate_PA_3.xml?rev=868&view=markup

I have run [4] the same code [5] 3 times.
On 1st run, method highSurrogate(int) [6] was inlined in Decoder$decode(...) [7] as hot ([1] line 
276-293), but not on 2nd run ([2] line 332-358).
Can someone explain this, because method highSurrogate() was executed 26,314,402 times ([3] line 1932) ?

In [2] (line 125, 215) hotspot log says:
@ 479   sun.nio.cs.ext.EUC_TW_C_d_b_reverse1$Decoder::decode  never executed
@ 95   java.lang.Character::highSurrogate  executed < MinInliningThreshold

On 3rd run, method highSurrogate(char,char) [6] was inlined in Decoder$decode(...) [8] as hot ([3] 
line 832-846), but not in 1st ([1] line 1012-1034) or 2nd run ([2] line 992-1014).
So I can see that hotspot inlining decision was different in each 3 runs:

                              [1]       [2]       [3]

highSurrogate(int)         276-293   332-358   473-490
[7] line 277                inline     call     inline

highSurrogate(char,char)  1012-1034  992-1014  832-846
[8] line 277                 call      call     inline


In [1] (line 853) hotspot log says:
@ 93   java.lang.Character::highSurrogate  never executed
@ 102   java.lang.Character::lowSurrogate  call site not reached

Here I don't understand the difference between 'never executed' and 'call site not reached'

-Ulf


[4]
https://java-nio-charset-enhanced.dev.java.net/source/browse/java-nio-charset-enhanced/branches/j7_EUC_TW/nbproject/configs/C_d_b_reverse1_2_PA.properties?rev=866&view=markup
[5]
https://java-nio-charset-enhanced.dev.java.net/source/browse/java-nio-charset-enhanced/branches/j7_EUC_TW/src/sun/nio/cs/ext/EUC_TWBenchmark.java?rev=866&view=markup
[6]
https://java-nio-charset-enhanced.dev.java.net/source/browse/java-nio-charset-enhanced/branches/j7_EUC_TW/src/java/lang/Character.java?rev=866&view=markup
[7]
https://java-nio-charset-enhanced.dev.java.net/source/browse/java-nio-charset-enhanced/branches/j7_EUC_TW/src/sun/nio/cs/ext/EUC_TW_C_d_b_reverse1.java?rev=866&view=markup
[8]
https://java-nio-charset-enhanced.dev.java.net/source/browse/java-nio-charset-enhanced/branches/j7_EUC_TW/src/sun/nio/cs/ext/EUC_TW_C_d_b_reverse2.java?rev=866&view=markup