orchestration.rst: add section `Link Latency and Synchronization Period`

doc/devel/arch.rst

@@ -20,6 +20,7 @@
   CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
   TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
   SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+.. _page-architectural-overview:
 
 ###################################
 Architectural Overview
@@ -138,6 +139,7 @@ interface-specific protocols, however, are fine. Similarly, we must ensure to
 not overwrite the base protocol's fields with something else.
 
 
+.. _sec-synchronization:
 
 Synchronization
 ---------------

doc/user/orchestration.rst

@@ -135,6 +135,31 @@ guest system and the value is an IO handle of the file to be copied over.
   :members: run_cmds, config_files
 
 
+***************************************
+Link Latency and Synchronization Period
+***************************************
+
+Most of the pre-defined simulators in :mod:`simbricks.orchestration.simulators`
+provide an attribute for tuning link latencies and the synchronization period.
+Both are configured in nanoseconds and apply to the message flow from the
+configured simulator to connected ones.
+
+Some simulators have interfaces for different link types, for example, NIC
+simulators based on :class:`~simbricks.orchestration.simulators.NICSim` have a
+PCIe interface to connect to a host and an Ethernet link to connect to the
+network. The link latencies can then be configured individually per interface
+type.
+
+The synchronization period defines the simulator's time between sending
+synchronization messages to connected simulators. Generally, for accurate
+simulations, you want to configure this to the same value as the link latency.
+This ensures an accurate simulation. With a lower value we don't lose accuracy,
+but we send more synchronization messages than necessary. The other direction is
+also possible to increase simulation performance by trading-off accuracy using a
+higher setting. For more information, refer to the section on
+:ref:`sec-synchronization` in the :ref:`page-architectural-overview`.
+
+
 .. _sec-command-line:
 
 ******************************