From: "Daniel P. Berrange" <berrange@redhat.com> --- docs/formatdomain.html.in | 25 ++++++++++++++++++++----- 1 files changed, 20 insertions(+), 5 deletions(-) diff --git a/docs/formatdomain.html.in b/docs/formatdomain.html.in index 814e270..c2eabc5 100644 --- a/docs/formatdomain.html.in +++ b/docs/formatdomain.html.in @@ -1016,11 +1016,23 @@ </dd> <dt><code>tickpolicy</code></dt> <dd> - The <code>tickpolicy</code> attribute determines how - missed ticks in the guest are handled, and can be "delay", - "catchup", "merge", or "discard". If the policy is - "catchup", there can be further details in - the <code>catchup</code> sub-element. + <p> + The <code>tickpolicy</code> attribute determines what + happens whens QEMU misses a deadline for injecting a + tick to the guest: + </p> + <dl> + <dt><code>delay</code></dt> + <dd>Continue to deliver ticks at the normal rate. The guest time will be delayed due to the late tick</dd> + <dt><code>catchup</code></dt> + <dd>Deliver ticks at a higher rate to catchup with the missed tick. The guest time should not be delayed once catch is complete.</dd> + <dt><code>merge</code></dt> + <dd>Merge the missed tick(s) into one tick and inject. The guest time may be delayed, depending on how the OS reacts to the merging of ticks</dd> + <dt><code>discard</code></dt> + <dd>Throw away the missed tick(s) and continue with future injection normally. The guest time may be delayed, unless the OS has explicit handling of lost ticks</dd> + </dl> + <p>If the policy is "catchup", there can be further details in + the <code>catchup</code> sub-element.</p> <dl> <dt><code>catchup</code></dt> <dd> @@ -1030,6 +1042,9 @@ and <code>limit</code>. </dd> </dl> + <p> + Note that hypervisors are not required to support all policies across all time sources + </p> </dd> <dt><code>frequency</code></dt> <dd> -- 1.7.7.6