Hi Sean, 



  That's an interesting difference between our performance measurements.



  You wrote:

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Note that 38% of the time is spent in GC; but allocation isn't that  

bad at all, at least with Xprof.  new array millicode is only 1.2%   

The big kahuna in allocation is clone(), which clocks in at 21.7% (up  

from 11.4% in Java 1.3.1).  This *should* basically boil down to a  

pointer increment and a memcpy.  (As opposed to new object(), which  

is a pointer increment and a bzero).  What I think is happening is  

that the cost of other elements are being optimized out in successive  

Java versions, so allocation is becoming more costly relative to them.

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  An alternative explanation is that my inline performance measurements 

are not as accurate as the -XProf. The new array allocation may trigger 

some form of GC and my measurement is including the time involved for GC.