> --- > > 604 Arrays.fill(elementData, newSize, size, null); > > In performance-critical code I would avoid Arrays.fill because it adds a > bit of overhead (unless it's intrinsified, which I don't think it is). >
Last week, I sent few benchmarks I did on array cleaning (zero fill) comparing Arrays.fill, System.arraycopy, Unsafe.setMemory ... Arrays.fill is the winner (always faster than arraycopy which use native code) by 10 - 20% ! I suspect aggressive hotspot optimizations (native code ?) because I agree Arrays.fill looks like a stupid for-loop ! Does somebody have clues explaining the Arrays.fill performance ? Is there an alternative way to clear an array giving the best possible performance (like c memset) ? it could be useful to have in JDK a native array fill implementation (System.fill ?) if it gives better performance. Laurent
