X-Git-Url: http://info.iut-bm.univ-fcomte.fr/pub/gitweb/simgrid.git/blobdiff_plain/27f991037b8d3e6181741b3ca41df44b64b66d4d..7d647f4a56279938a6bfafe70a563fcdb8f3e6bb:/include/simgrid/s4u/Activity.hpp

diff --git a/include/simgrid/s4u/Activity.hpp b/include/simgrid/s4u/Activity.hpp
index feb9d7b6de..e3da5b28f4 100644
--- a/include/simgrid/s4u/Activity.hpp
+++ b/include/simgrid/s4u/Activity.hpp
@@ -14,7 +14,17 @@ namespace s4u {
 /** @brief Activities
  *
  * This class is the ancestor of every activities that an actor can undertake.
- * That is, of the actions that do take time in the simulated world.
+ * That is, activities are all the things that do take time to the actor in the simulated world.
+ *
+ * They are somewhat linked but not identical to simgrid::kernel::resource::Action,
+ * that are stuff occurring on a resource:
+ *
+ * - A sequential execution activity encompasses 2 actions: one for the exec itself,
+ *   and a time-limited sleep used as timeout detector.
+ * - A point-to-point communication activity encompasses 3 actions: one for the comm itself
+ *   (which spans on all links of the path), and one infinite sleep used as failure detector
+ *   on both sender and receiver hosts.
+ * - Synchronization activities may possibly be connected to no action.
  */
 class XBT_PUBLIC Activity {
   friend Comm;