Re: [PATCH] x86: Support always running TSC on Intel CPUs

From: Joe Korty
Date: Tue Nov 18 2008 - 10:59:37 EST


On Tue, Nov 18, 2008 at 09:09:52AM +0100, Ingo Molnar wrote:
>
> * Venki Pallipadi <venkatesh.pallipadi@xxxxxxxxx> wrote:
>
> > + if (c->x86_power & (1 << 8)) {
> > set_cpu_cap(c, X86_FEATURE_CONSTANT_TSC);
> > + set_cpu_cap(c, X86_FEATURE_NOSTOP_TSC);
> > + }
>
> hm, the naming is a bit confusing. We now have 3 variants:
>
> X86_FEATURE_TSC
> X86_FEATURE_CONSTANT_TSC
> X86_FEATURE_NOSTOP_TSC
>
> NOSTOP_TSC is basically what CONSTANT_TSC should have been to begin
> with ;-)
>
> i'd suggest to rename it to this:
>
> X86_FEATURE_TSC
> X86_FEATURE_CONSTANT_FREQ_TSC
> X86_FEATURE_STABLE_TSC
>
> ... with CONSTANT_FREQ_TSC not having any real role in the long run.
> (it's similarly problematic to a completely unstable TSC)
>
> does this sound ok?


To me, the new naming has the same head-scratching potential
as the old....

How about:

X86_FEATURE_TSC
X86_FEATURE_STABLE_TSC_OBSOLETE
X86_FEATURE_STABLE_TSC

Joe
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