On Wed, Aug 04, 2021 at 09:34:13PM -0700, Andi Kleen wrote:

quoted

My current thought is that if more than (say) 100 consecutive attempts
to read the clocksource get hit with excessive delays, it is time to at
least do a WARN_ON(), and maybe also time to disable the clocksource
due to skew.  The reason is that if reading the clocksource -always-
sees excessive delays, perhaps the clock driver or hardware is to blame.

Thoughts?

On TDX this would be fatal because we don't have a usable fallback source

(just jiffies). Better try as hard as possible.

At some point, won't the system's suffering in silence become quite the
disservice to its users?

One alternative would be to give a warning splat, but avoid reporting
skew.  Unless there is the traditional 62.5ms of skew, of course.

							Thanx, Paul