On Mon, Jan 13, 2020 at 1:43 PM Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote: > > On Mon, Jan 13, 2020 at 11:43:18AM +0000, Singh, Balbir wrote: > > For your original comment, just wanted to clarify the following: > > > > 1. After hibernation, the machine can be resumed on a different but compatible > > host (these are VM images hibernated) > > 2. This means the clock between host1 and host2 can/will be different > > > > In your comments are you making the assumption that the host(s) is/are the > > same? Just checking the assumptions being made and being on the same page with > > them. > > I would expect this to be the same problem we have as regular suspend, > after power off the TSC will have been reset, so resume will have to > somehow bridge that gap. I've no idea if/how it does that. In general, this is done by timekeeping_resume() and the only special thing done for the TSC appears to be the tsc_verify_tsc_adjust(true) call in tsc_resume(). > I remember some BIOSes had crazy TSC ideas for suspend2ram, and we grew > tsc_restore_sched_clock_state() for it. > > Playing crazy games like what you're doing just isn't it though. Right.
