On 19.11.2009, at 14:34, Avi Kivity wrote: > From: Glauber Costa <glommer@xxxxxxxxxx> > > When we migrate a kvm guest that uses pvclock between two hosts, we may > suffer a large skew. This is because there can be significant differences > between the monotonic clock of the hosts involved. When a new host with > a much larger monotonic time starts running the guest, the view of time > will be significantly impacted. > > Situation is much worse when we do the opposite, and migrate to a host with > a smaller monotonic clock. > > This proposed ioctl will allow userspace to inform us what is the monotonic > clock value in the source host, so we can keep the time skew short, and > more importantly, never goes backwards. Userspace may also need to trigger > the current data, since from the first migration onwards, it won't be > reflected by a simple call to clock_gettime() anymore. So I assume without this feature there's no way to have a reliable kvmclock inside the guest? Isn't it stable material then? Alex-- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
