Bug 712824

Summary: after ping-pong migrating 11 times, guest time drift will exceed 1 second
Product: Red Hat Enterprise Linux 5 Reporter: FuXiangChun <xfu>
Component: kvmAssignee: Virtualization Maintenance <virt-maint>
Status: CLOSED WONTFIX QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: medium    
Version: 5.7CC: juzhang, mkenneth, rhod, virt-maint
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2011-06-21 17:30:20 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:

Description FuXiangChun 2011-06-13 09:49:33 UTC 
Description of problem:
after every time migrated, offset value will add about 0.1 second.

Version-Release number of selected component (if applicable):
host info:
# uname -r
2.6.18-266.el5
# rpm -qa|grep kvm
kvm-83-236.el5

guest info:


How reproducible:


Steps to Reproduce:
1.
(1)src host:
/usr/libexec/qemu-kvm -M rhel5.4.4 -rtc-td-hack -usbdevice tablet -no-hpet -drive file=/mnt/rhel5.7-32.raw,if=virtio,boot=on,werror=stop,cache=none,format=raw,media=disk -cpu qemu64 -smp 4,sockets=2,cores=1,threads=2 -m 2G -net nic,macaddr=00:12:24:57:a8:2e,model=virtio,vlan=0 -net tap,script=/etc/qemu-ifup,vlan=0 -uuid `uuidgen` -boot c -balloon none -notify all -rtc-td-hack -no-kvm-pit-reinjection -monitor stdio -vnc :1 
(2)des host:
/usr/libexec/qemu-kvm -M rhel5.4.4 -rtc-td-hack -usbdevice tablet -no-hpet -drive file=/mnt/rhel5.7-32.raw,if=virtio,boot=on,werror=stop,cache=none,format=raw,media=disk -cpu qemu64 -smp 4,sockets=2,cores=1,threads=2 -m 2G -net nic,macaddr=00:12:24:57:a8:2e,model=virtio,vlan=0 -net tap,script=/etc/qemu-ifup,vlan=0 -uuid `uuidgen` -boot c -balloon none -notify all -rtc-td-hack -no-kvm-pit-reinjection -monitor stdio -vnc :1 -incoming tcp:0:5555

2.add option divider=10 lpj=n clocksource=acpi_pm to Guest kernel cmdline 

3. sync two host and guest time before do migrate
  ntpdate -q clock.redhat.com

3. do 11 times ping-pong migration 
  
Actual results:
offset value exceed 1 second

Expected results:
offset value always less then 1 second.

Additional info:
Comment 1 Ronen Hod 2011-06-21 17:30:20 UTC 
As this is not our default clock source (KVMclock), and the problem can be taken care of by NTP, this bug will not be fixed for RHEL5.