[9fans] Go: FP in note handler

[Kenny Lasse Hoff Levinsen <kennylevinsen@gmail.com>]

For those interested in the matter, I have opened https://github.com/golang/go/issues/14471

I mention potentially reenabling duffcopy by writing some magic note handler code that avoid the regular copy and zero optimizations, but I’m not entirely sure if that’s a plausible path. If it is, I think it would bring benefit, both in the performance gained by duffcopy/duffzero, as well as the chances of this happening again. It is, however, slightly annoying to do, as you cannot use copy(), make() or even strings or byte array literals, as these will trip duffcopy and duffzero. Any comments to my silly idea?

Best regards,
Kenny Levinsen

> On 22 Feb 2016, at 18:16, Richard Miller <miller@hamnavoe.com> wrote:
> 
>> The trace of goexitsall still contain FP register access (XORPS and duffzero which contains MOVUPS)
> 
> Sorry, in that case I think my patch is not relevant for your issue
> (but it does prevent a deadlock on multiprocessors which you might
> also run into...)
>