Unsafe.{get,put}-X-Unaligned performance

[John Rose]

On Mar 10, 2015, at 12:02 PM, Andrew Haley <aph at redhat.com> wrote:
> 
> The new algorithm is slightly slower because of branch misprediction.
> 
> old:  2.17 IPC, 0.08% branch-misses, 91,965,281,215 cycles
> new:  1.23 IPC, 6.11% branch-misses, 99,925,255,682 cycles
> 
> ...but it executes fewer instructions so we're only talking about
> some 10% slowdown.  I think this is the worst case (or something
> close to the worst case) for the new algorithm.
> 
> So, I think we're OK performance-wise.

I agree.

> 
> John: I'm waiting for an answer to my question here before I submit
> a webrev for approval.
> 
> http://mail.openjdk.java.net/pipermail/panama-dev/2015-March/000099.html <http://mail.openjdk.java.net/pipermail/panama-dev/2015-March/000099.html>

(Answered.)

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