+/** Computation Activity, representing the asynchronous executions.
+ *
+ * @beginrst
+ * Most of them are created with :cpp:func:`simgrid::s4u::this_actor::exec_init()` or
+ * :cpp:func:`simgrid::s4u::Host::execute()`, and represent a classical (sequential) execution. This can be used to
+ * simulate some computation occurring in another thread when the calling actor is not blocked during the execution.
+ *
+ * You can also use :cpp:func:`simgrid::s4u::this_actor::parallel_execute()` to create *parallel* executions. These
+ * objects represent distributed computations involving computations on several hosts and communications between them.
+ * Such objects can for example represent a matrix multiplication done with ScaLAPACK on a real system. Once created,
+ * parallel Exec are very similar to the sequential ones. The only difference is that you cannot migrate them, and their
+ * remaining amount of work can only be defined as a ratio. See the doc of :cpp:func:`simgrid::s4u::Exec::get_remaining`
+ * and :cpp:func:`simgrid::s4u::Exec::get_remaining_ratio` for more info.
+ * @endrst
+ */
+class XBT_PUBLIC Exec : public Activity_T<Exec> {
+#ifndef DOXYGEN
+ friend kernel::activity::ExecImpl;
+ friend kernel::EngineImpl; // Auto-completes the execs of maestro (in simDAG)
+#endif
+
+ bool parallel_ = false;
+
+protected:
+ explicit Exec(kernel::activity::ExecImplPtr pimpl);
+
+ void reset() const;
+
+ static xbt::signal<void(Exec const&)> on_start;
+