On Sat, Mar 14, 2020 at 10:05:20PM +0200, Liran Alon wrote: > Michael, you can also refer to this VMware time-keeping whitepaper: > https://www.vmware.com/pdf/vmware_timekeeping.pdf. > According to section "Initializing and Correcting Wall-Clock Time": > """ > VMware Tools can also optionally be used to correct long‐term drift and > errors by periodically > resynchronizing the virtual machine’s clock to the host’s clock, but the > current version at this writing is limited. > In particular, in guest operating systems other than NetWare, it does not > correct errors in which the guest clock > is ahead of real time, only those in which the guest clock is behind. > > """
This talks about guest time. What this does not mention is whether hosts need to employ any mechanisms to synchronise wall clock between hosts. > If I understand correctly, this seems to validate my assumption that current > implementation for CMD_GETTIME is sufficient. So I am concerned this does not interact well with other time sources in QEMU. For example, it's very useful to set guest time with -rtc base flag. Can you use qemu_get_timedate? -- MST
