Re: [PATCH] ARM: NEON detected memcpy.

["Shih-Yuan Lee (FourDollars)" <sylee@canonical.com>]

Hi Joseph,

I know there is some legal homework but I don't know how to do it.
Could you provide more details about how to put such copyright
assignment (with some real example is better)?

About raised power consumption and context switch costs, I may be able
to add some option in configure for the users to decide if they want
to use this feature or not.
How do you think?

Regards,
$4

On Wed, Apr 3, 2013 at 11:08 PM, Joseph S. Myers
<joseph@codesourcery.com> wrote:
> On Wed, 3 Apr 2013, Shih-Yuan Lee (FourDollars) wrote:
>
>> I am working on the NEON detected memcpy.
>> This is based on what Siarhei Siamashka did at 2009 [1].
>
> I still don't see any copyright assignment on file (whether individual
> with an employer disclaimer, or corporate) that would cover that work.
> Without one, we can't use it, and I advise anyone working on NEON memcpy
> not to look at it.
>
> I was previously told by people at ARM that NEON memcpy wasn't a good idea
> in practice because of raised power consumption, context switch costs etc.
> from using NEON in processes that otherwise didn't use it, even if it
> appeared superficially beneficial in benchmarks.
>
> --
> Joseph S. Myers
> joseph@codesourcery.com