[HBASE-17233] See if we should replace System.arrayCopy with Arrays.copyOfRange

• Type: Improvement
• Status: Open
• Priority: Major
• Resolution: Unresolved
• Affects Version/s: 2.0.0
• Assignee: ramkrishna.s.vasudevan
• Reporter: ramkrishna.s.vasudevan
• Created: 02/Dec/16 07:29
• Updated: 28/May/19 19:08

Description

Just saw this interesting comment in PB code. Since we deal with byte[] extensively (when we are onheap) we do lot of copies too.

* <p>One of the noticeable costs of copying a byte[] into a new array using
   * {@code System.arraycopy} is nullification of a new buffer before the copy. It has been shown
   * the Hotspot VM is capable to intrisicfy {@code Arrays.copyOfRange} operation to avoid this
   * expensive nullification and provide substantial performance gain. Unfortunately this does not
   * hold on Android runtimes and could make the copy slightly slower due to additional code in
   * the {@code Arrays.copyOfRange}. 

So since we are hotspot VM we could see if the places we use System.arrayCopy can be replaced with Arrays.copyOfRange.