Re: [tip:x86/urgent] x86/cpufeature: Add AVX512_4VNNIW and AVX512_4FMAPS features

[Luc, Piotr]

On Mon, 2016-10-17 at 00:42 +0200, Borislav Petkov wrote:
> On Sun, Oct 16, 2016 at 11:42:26AM -0700, hpa@xxxxxxxxx wrote:
> > 
> > It's needlessly adding complexity for no reason, at least for the
> 
> What complexity? The init_scattered_cpuid_features() version is a
> trivial patch in comparison to the current version.
> 
> > 
> > leaves that are going to add bits over time.
> 
> Sure, except they don't get added or we don't need them or whatever,
> and
> we end up with only a small number of bits actually being used.
> 
> I don't mind moving them to x86_capability later, when a high
> percentage
> of the respective leaf is actually being used but not for a couple of
> bits. That's just waste.
> 
> > 
> > The x86_capability array is not an expensive resource.
> 
> 0.1% here, 0.1% there, the creeping bloat thing.
> 
> And again, the init_scattered_cpuid_features() hunk is much smaller.
> 
I agree, the scattered solution reduces data segment footprint in case
many cores.

Regards,
Piotr