added the guidlines to enable 'start_event_grains' config

modules/client-configuration/pages/tshoot-clients.adoc

@@ -88,6 +88,39 @@ Therefore you must not mount [filename]``/tmp`` with the [option]``noexec`` opti
 
 
 
+== Passing Grains to a Start Event
+
+Every time a Salt client starts, it passes the ``machine_id`` grain to {productname}. {productname} uses this grain to determine if the client is registered.
+This process requires a synchronous Salt call. Synchronous Salt calls block other processes, so if you have a lot of clients start at the same time, the process could create significant delays.
+
+To overcome this problem, a new feature has been introduced in Salt to avoid making a separate synchronous Salt call.
+
+To use this feature, you can add a configuration parameter to the client configuration, on clients that support it.
+
+To make this process easier, you can use the ``mgr_start_event_grains.sls`` helper Salt state.
+
+[NOTE]
+====
+This only applies to already registered clients.
+If you registered your Salt client recently, this config parameter is added by default.
+====
+
+
+On the {productname} Server, at the command prompt, use this command to enable the ``start_event_grains`` configuration helper:
+
+----
+salt '*' state.sls util.mgr_start_event_grains
+----
+
+This command adds the required configuration into the client's configuration file, and applies it when the client is restarted.
+If you have a large number of clients, you can execute the command in batch mode instead:
+
+----
+salt --batch-size 50 '*' state.sls mgr_start_event_grains
+----
+
+
+
 == SSL errors
 
 On SLES{nbsp}11 systems, clients can sometimes have SSL errors which make some operations unusable, including package management and bootstrapping.