23.17. Timer Element Attributes

The name element contains the name of the time source to be used. It can have any of the following values:

Table 23.12. Name attribute values

Value Description
pit Programmable Interval Timer - a timer with periodic interrupts. When using this attribute, the tickpolicy delay becomes the default setting.
rtc Real Time Clock - a continuously running timer with periodic interrupts. This attribute supports the tickpolicy catchup sub-element.
kvmclock KVM clock - the recommended clock source for KVM guest virtual machines. KVM pvclock, or kvm-clock allows guest virtual machines to read the host physical machine’s wall clock time.
The track attribute specifies what is tracked by the timer, and is only valid for a name value of rtc.

Table 23.13. track attribute values

Value Description
boot Corresponds to old host physical machine option, this is an unsupported tracking option.
guest RTC always tracks the guest virtual machine time.
wall RTC always tracks the host time.
The tickpolicy attribute and the values dictate the policy that is used to pass ticks on to the guest virtual machine.

Table 23.14. tickpolicy attribute values

Value Description
delay Continue to deliver at normal rate (ticks are delayed).
catchup Deliver at a higher rate to catch up.
merge Ticks merged into one single tick.
discard All missed ticks are discarded.
The present attribute is used to override the default set of timers visible to the guest virtual machine. The present attribute can take the following values:

Table 23.15. present attribute values

Value Description
yes Force this timer to be visible to the guest virtual machine.
no Force this timer to not be visible to the guest virtual machine.