Re: [GIT PULL] isolation: 1Hz residual tick offloading v4

[Peter Zijlstra]

On Mon, Jan 29, 2018 at 10:33:16AM -0500, Luiz Capitulino wrote:
> Cool, passing tsc=reliable worked for me. I finally got to the tick to
> go completely away. While I agree that fixing that is beyond the scope
> of this series, I think we should improve it anyway since it will probably
> come up for people trying the new nohz_full=.

The only way to fix that is to audit all BIOS code :/ Short of that, we
need to periodically test the TSC on each CPU/SOCKET to verify its still
in step with expectation.

Sadly MSR_IA32_TSC and MSR_IA32_TSC_ADJUST are writable registers and
BIOS monkeys occasionally write to them for 'raisins-of-insanity'.