Re: [tip:x86/asm] x86: Prefer TZCNT over BFS

From: Ingo Molnar
Date: Mon Sep 17 2012 - 06:00:46 EST



* Jan Beulich <JBeulich@xxxxxxxx> wrote:

> >>> On 14.09.12 at 23:14, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> > On Thu, Sep 13, 2012 at 11:23 PM, tip-bot for Jan Beulich
> > <JBeulich@xxxxxxxx> wrote:
> >>
> >> x86: Prefer TZCNT over BFS
> >
> > This patch is insane.
>
> I'm not going to defend this simple and strait forward a patch
> to such a reply, so Ingo, just drop it to please Linus, even
> though I can't see what's _this_ bad about it.

Well, the problem is the complication of the dependencies, which
obscures the logic and makes it hard to maintain going forward.

Linus's suggestion is to introduce CONFIG_X86_TZCNT as an add-on
patch that cleans up and documents what this is all about.

Would you be willing to do such a patch?

Thanks,

Ingo
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