Re: [PATCH v10 1/7] x86/tsc: remove tsc_disabled flag

From: Thomas Gleixner
Date: Tue Jun 19 2018 - 16:58:17 EST


On Tue, 19 Jun 2018, Peter Zijlstra wrote:

> On Tue, Jun 19, 2018 at 09:12:45PM +0200, Thomas Gleixner wrote:
> > On Tue, 19 Jun 2018, Peter Zijlstra wrote:
> > > It does not; there is TSC usage even if you boot with notsc on. See how
> > > it does not clear X86_FEATURE_TSC for instance.
> >
> > Well, kinda. There is some stuff in the apic calibration which uses TSC
> > independent of tsc_disabled, but that's about it.
>
> Still, that precludes booting on hardware without TSC, so what's the
> point of having notsc? I'm all for killing the thing.

I'm not arguing against removing it. I just refuse to accept changelogs
which suggest that there is no functional change.

Thanks,

tglx