RFR (S) 8146801: Allocating short arrays of non-constant size is slow

Vladimir Ivanov vladimir.x.ivanov at oracle.com
Wed Mar 2 13:05:41 UTC 2016

>   I've no idea whether it would matter in real code.  AFAIK, prefetchnta
> will bring the line into L1 on modern Intel.  Prefetching beyond the
> small array allocation would seem undesirable as it increases
> instruction stream size for no benefit and may bring in lines that
> aren't needed at all.
Still guessing, but considering it still prefetches lines from current 
TLAB, consequent allocations may benefit. Actual performance should 
heavily depend on allocation rate though.

Best regards,
Vladimir Ivanov

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