ReRe: performance (shellsort experiments)
Tom Tromey
tromey@cygnus.com
Tue Aug 17 14:48:00 GMT 1999
>>>>> "Norman" == Norman Hendrich <hendrich@tech.informatik.uni-hamburg.de> writes:
>> [Object sorting with _Jv_CheckArrayStore(): 59 seconds]
>> [Object sorting without _Jv_CheckArrayStore(): 17 seconds]
>> [Double sorting (=specific type): 16 seconds]
Norman> Interesting! I have often wondered how much runtime overhead
Norman> the 'generic type' approach to data structures in Java really
Norman> implied. I would never have guessed a factor of almost four,
Norman> however.
It can be less. Our implementation of _Jv_CheckArrayStore (actually
Class.isAssignableFrom) is particularly naive.
Norman> As the above result shows, having a smart compiler that
Norman> detects this situation (reassigning an object to an array)
Norman> might really help
Yeah.
Tom
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