Re: x86: per-cpu tmp vas

[Maxime Villard <max%m00nbsd.net@localhost>]

Le 30/01/2017 à 04:03, Takashi YAMAMOTO a écrit :
> hi,
>
> On Sat, Jan 28, 2017 at 6:42 PM, Maxime Villard <max%m00nbsd.net@localhost <mailto:max%m00nbsd.net@localhost>> wrote:
>
>     I've updated my patch. The previous one was completely wrong. However, I'm not
>     going to commit it now.
>
>     For the record: in fact, I cannot measure the performance because of two issues
>      - our PMCs do not support SMP, which is problematic since false-sharing occurs
>        with at least two CPUs. I can't get the interesting measurement MSRs on my
>        AMD.
>
>
> tprof used to work fine on smp when i was using it actively.
> no idea about your cpu model though.

Indeed - I was more looking at i386/pmc.c. I have tried tprof, but after reading
the AMD spec I figured out that my AMD Athlon x3 does not support PMCs at all
(no CPUID_PCENB). I will try on an AMD Phenom II, but I suspect it does not
support PMCs either.