Somehow the Xen side (of moving the vcpu info containing the vcpu time info from the shared struct to the per-cpu area through the register hypercall) has not changed much between 12.04 and 14.04. The vcpu_clock has though. That involves some slightly different memory barriers. What has not changed is using a rdtsc instruction together with the timestamp from the time info to get a time delta. Which could again point to some TSC issues. But then, this always seems to get triggered exactly at the time of moving the vcpu info. So maybe some race related to the slightly different code of accessing the data. But nothing that easily comes to my mind.
-- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1349883 Title: dmesg time wildly incorrect on paravirtual EC2 instances. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1349883/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs
