Re: RFC: Petition Intel/AMD to add POPF_IF insn

[Denys Vlasenko]

On 08/18/2016 07:47 PM, Denys Vlasenko wrote:
> On 08/18/2016 07:24 PM, Linus Torvalds wrote:
> > That said, your numbers really aren't very convincing. If popf really
> > is just 10 cycles on modern Intel hardware, it's already fast enough
> > that I really don't think it matters.
>
> It's 20 cycles. I was wrong in my email, I forgot that the insn count
> also counts "push %ebx" insns.
>
> Since I already made a mistake, let me double-check.
>
> 200 million iterations of this loop execute under 17 seconds:
>
>   400100:    b8 00 c2 eb 0b           mov    $0xbebc200,%eax # 1000*1000*1000

Grr. It's 200*1000*1000, not one billion. Sorry.