RFR: 8159063: aarch64: optimise unaligned array copy long

Vladimir Kozlov vladimir.kozlov at oracle.com
Tue Jun 14 18:40:08 UTC 2016

Mark R. sent mail about approval process:


"  - If you own a JEP or a small enhancement that is not yet complete then
     you can request an FC extension as follows: Update the JBS issue to
     add a comment whose first line is "FC Extension Request".  In that
     comment describe the remaining work to be done, the risk level, a
     brief justification, and your best estimate of the date by which the
     feature will be complete.  Add the label "jdk9-fc-request" to the

If you have reviewed changes add link to the RFE.


On 6/8/16 9:01 AM, Vladimir Kozlov wrote:
> Please, hold on pushing this RFE into jdk 9. We are post FC and it needs
> approval.
> Thanks,
> Vladimir
> On 6/8/16 8:25 AM, Edward Nevill wrote:
>> Hi,
>> Please review the following webrev
>> http://cr.openjdk.java.net/~enevill/8159063/webrev
>> JIRA Issue: https://bugs.openjdk.java.net/browse/JDK-8159063
>> This webrev optimises the code generate for copy array long to ensure
>> that loads/stores are always done on 128 bit boundaries.
>> This can be switched on/off with -XX:+/-AvoidUnalignedAccesses which is
>> set by default for those partners where there is a benefit.
>> The following is my test case.
>> http://cr.openjdk.java.net/~enevill/8159063/ArrayCopyAligned.java
>> To run do
>> java ArrayCopyAligned <iters> <start> <end> <step>
>> This shows the results for partners A and B with the parameters 10 0
>> 1024 32.
>> http://cr.openjdk.java.net/~enevill/8159063/arraycopy.pdf
>> OK to push to jdk8u now (and later to jdk9)?
>> Thanks,
>> Ed.

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