Re: [GIT PULL] timer fixes

[Linus Torvalds]

On Tue, Dec 17, 2019 at 11:30 AM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
>
> What alternatives are there? That is, we normally only use HPET to
> double check nobody messed up the TSC.

The thing is HPET seems to be _less_ reliable than the TSC we're
checking these days.

If that's the only use-case for HPET, we should just stop doing it.

> We can't just blindly trust TSC across everything x86.

No, but we can trust it when it's a modern CPU.

The HPET seems to get disabled on all the modern platforms, why do we
even have it enabled by default?

We should do the HPET cross-check only when we know the TSC might be
unreliable, I suspect.

           Linus