RFR 8151163 All Buffer implementations should leverage Unsafe unaligned accessors

[Aleksey Shipilev]

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!

Cheers,
-Aleksey