RFR 8151163 All Buffer implementations should leverage Unsafe unaligned accessors

[Paul Sandoz]

> On 10 Mar 2016, at 18:14, Aleksey Shipilev <aleksey.shipilev at oracle.com> wrote:
> 
> On 03/10/2016 08:06 PM, Paul Sandoz wrote:
>>> On 8 Mar 2016, at 19:27, Paul Sandoz <Paul.Sandoz at oracle.com> wrote:
>>> 
>>>>> The changes in this webrev take advantage of those for JDK-8149469
>>>>> and apply the unsafe double addressing scheme so certain byte buffer
>>>>> view implementations can work across heap and direct buffers. This
>>>>> should improve the performance on x86 for:
>>>> 
>>>> I understand the idea, but I think we would need to verify this before
>>>> pushing.
>>>> 
>>> 
>>> Admittedly i am leaning on the rational/motivation for the previous changes to use Unsafe unaligned accessors.
>>> 
>>> I less confident about the impact on non-x86 platforms.
>>> 
>>> I have some VarHandles related benchmark code [*] i can use to get some numbers.
>>> 
>> 
>> Here is some prelimiary perf numbers for x86 so far:
>> 
>>  http://cr.openjdk.java.net/~psandoz/jdk9/JDK-8151163-buffer-unsafe-unaligned-access/perf/ArrayViewTest.java
> 
> Okay, the performance data looks good. This addresses my concerns for
> this issue, thanks!
> 

Thanks, i added you as a reviewer.

Paul.