[Insight-developers] -Wover-aligned warnings on Rogue7 dashboard

[Sean McBride]

On Tue, 21 May 2013 11:30:40 -0400, Bradley Lowekamp said:

>It's for performance reasons to prevent false sharing. This was a
>significant bottle neck in the v3 Mattes Mutual Information metric, so
>it was quite worth the effort.
>
>Is this the cause for any failing tests?

I don't know.  There are a lot of failing tests on Rogue7 though, so maybe...

>Or is this just a warning, that
>the alignment will be ignored?

I believe it's saying that 'AlignedPerThreadType' was marked as *requiring* 64 bytes of alignment (via alignas(64)), but then 'new' is used and that 'new' is unable give that alignment.

Sounds like you're saying that 64 byte alignment is not actually required, but better for performance.

I guess the thing is that alignas(64) is not specifying an optional hint, which is what you want, but specifying a minimum requirement.

Cheers,

-- 
____________________________________________________________
Sean McBride, B. Eng                 sean at rogue-research.com
Rogue Research                        www.rogue-research.com 
Mac Software Developer              Montréal, Québec, Canada