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Type:
Enhancement
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Resolution: Unresolved
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Priority:
P4
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Affects Version/s: 9, 10
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Component/s: hotspot
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x86
Originally found here:
http://stackoverflow.com/questions/25078285/replacing-a-32-bit-loop-count-variable-with-64-bit-introduces-crazy-performance
It seems newish Intel x86 processors treat the destination register for popcnt as the input, and wait for it to be ready in order to continue execution.
http://stackoverflow.com/questions/25078285/replacing-a-32-bit-loop-count-variable-with-64-bit-introduces-crazy-performance
It seems newish Intel x86 processors treat the destination register for popcnt as the input, and wait for it to be ready in order to continue execution.