Re: cputime takes cstate into consideration

From: Peter Zijlstra
Date: Wed Jun 26 2019 - 15:21:22 EST

On Wed, Jun 26, 2019 at 06:55:36PM +0000, Raslan, KarimAllah wrote:

> If the host is completely in no_full_hz mode and the pCPU is dedicated to a 
> single vCPU/task (and the guest is 100% CPU bound and never exits), you would 
> still be ticking in the host once every second for housekeeping, right? Would 
> not updating the mwait-time once a second be enough here?

People are trying very hard to get rid of that remnant tick. Lets not
add dependencies to it.

IMO this is a really stupid issue, 100% time is correct if the guest
does idle in pinned vcpu mode.