Re: [PATCH v14 20/25] x86/tsc: calibrate tsc only once

Pavel Tatashin
2018-07-19T18:38:09Z

On Thu, Jul 19, 2018 at 12:49 PM Pavel Tatashin
<pasha.tatashin@oracle.com> wrote:
>
> > So create two functions. native_...early..() and native....(). The early
> > one does not contain the hpet/pmtimer stuff and it replaces the ops.pointer
> > with the late one which contains all of it.
>
> Good idea. Actually, the late one will contain only hpet/pmtimer and I
> will set it only if tsc frequency was not determined only.

If we determined tsc early in boot using one of the quick methods:
from cpuid/msr/quick_pit, can we assume that frequencies of all other
CPUs will be determined the same way? Or do we still have to fallback
to PIT/HPET/PMTIMER? I wondering if we support heterogeneous
multi-socket platforms with different CPUs, because that the only
platforms where I see such scenario is possible.

Thank you,
Pavel