To avoid timing issue (slow or too fast clock in a guest) you should make sure you use the right clock source in your KVM guest.
Linux:
The best source clock is the kvm-clock (exist from 2.6.27 and above).
To see what is used, just run in the Linux guest the following command:
Output: kvm-clock
Windows:
Standard acpi HAL uses the rtc clock by default. As long as
you use the -rtc-td-hack it won't drift (-rtc-td-hack is automatically used on Proxmox VE)
When the TSC is not stable on the host or the host cpu might get into
deep sleep state (c2), you better use another source clock in the guest
- for windows it should be the pmtimer (using the boot.ini).
The boot.ini can look like this (here is the boot.ini from a WinXP):
Linux:
The best source clock is the kvm-clock (exist from 2.6.27 and above).
To see what is used, just run in the Linux guest the following command:
Code:
cat /sys/devices/system/clocksource/clocksource0/current_clocksourceWindows:
Standard acpi HAL uses the rtc clock by default. As long as
you use the -rtc-td-hack it won't drift (-rtc-td-hack is automatically used on Proxmox VE)
When the TSC is not stable on the host or the host cpu might get into
deep sleep state (c2), you better use another source clock in the guest
- for windows it should be the pmtimer (using the boot.ini).
The boot.ini can look like this (here is the boot.ini from a WinXP):
Code:
[boot loader]
timeout=30
default=multi(0)disk(0)rdisk(0)partition(1)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(1)\WINDOWS="Microsoft Windows XP Professional" /noexecute=optin /fastdetect /usepmtimer