Re: [PATCH v3 1/2] x86/tsc: add a timer to make sure tsc_adjust is always checked

[Nicolas Saenz Julienne]

Hi Feng, Thomas,

> On Wed, Nov 17, 2021 at 10:37:51AM +0800, Feng Tang wrote:
> Normally the tsc_sync will get checked every time system enters idle state,
> but Thomas Gleixner mentioned there is still a caveat that a system won't
> enter idle [1], either because it's too busy or configured purposely to not
> enter idle. Setup a periodic timer (every 10 minitues) to make sure the
> check is always on.
> 
> [1]. https://lore.kernel.org/lkml/875z286xtk.fsf@xxxxxxxxxxxxxxxxxxxxxxx/
> Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx>

I can see this timer interrupting my system's nohz_full CPUs. It'd be nice to
be able to avoid the noise. A solution is using 'tsc=reliable', but IIUC this
is not what the flag was created for. Any ideas/suggestions?

Regards,
Nicolas