Request for reviews (M): 7081933: Use zeroing elimination optimization for large array
vladimir.kozlov at oracle.com
Thu Sep 22 22:35:18 UTC 2011
7081933: Use zeroing elimination optimization for large array
Currently when a new array does not fit into TLAB (big array
(FastAllocateSizeLimit) or most common case when no space left in TLAB) C2 calls
runtime which does allocation and zeroing. But zeroing is not needed if
allocation is followed by arraycopy which initialize it (ReduceBulkZeroing
Add a new runtime call _new_array_nozero_Java for such case and use it only for
type arrays since obj arrays have to be initialized if deoptimization happened
on the return from RT to compiled code.
These changes does not affect refworkload scores (including jbb2005). But
crypto.aes (jvm2008) score improved around 10% on sparc. I don't see improvement
on x86, may by because it has different crypto code.
Added small fix to prefetch code in sparc arraycopy stub.
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