Red Hat Training
A Red Hat training course is available for Red Hat Enterprise Linux
23.16. 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. |
