+These objects are convenient abstractions of parallel
+computational kernels that span over several machines, such as a
+PDGEM and the other ScaLAPACK routines. Note that this only works
+with the "ptask_L07" host model (``--cfg=host/model:ptask_L07``).
+
+This example demonstrates several kinds of parallel tasks: regular
+ones, communication-only (without computation), computation-only
+(without communication), synchronization-only (neither
+communication nor computation). It also shows how to reconfigure a
+task after its start, to change the number of hosts it runs onto.
+This allows simulating malleable tasks.
+
+.. tabs::
+
+ .. example-tab:: examples/cpp/exec-ptask/s4u-exec-ptask.cpp
+
+ See also :cpp:func:`simgrid::s4u::this_actor::parallel_execute()`.
+
+ .. example-tab:: examples/python/exec-ptask/exec-ptask.py
+
+ See also :ref:`simgrid.this_actor.parallel_execute()`
+
+Ptasks play well with the host energy plugin, as shown in this example.
+There is not much new compared to the above ptask example or the
+:ref:`examples about energy <s4u_ex_energy>`. It just works.
+
+.. tabs::
+
+ .. example-tab:: examples/cpp/energy-exec-ptask/s4u-energy-exec-ptask.cpp
+
+ .. example-tab:: examples/c/energy-exec-ptask/energy-exec-ptask.c
+
+.. _s4u_ex_exec_failure:
+
+Dealing with host failures
+^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+This examples shows how to survive to host failure exceptions that occur when an host is turned off. The actor do not get notified when the host
+on which they run is turned off: they are just terminated in this case, and their ``on_exit()`` callback gets executed. For remote executions on
+failing hosts however, any blocking operation such as ``exec`` or ``wait`` will raise an exception that you can catch and react to. See also
+:ref:`howto_churn`,
+:ref:`this example <s4u_ex_platform_state_profile>` on how to attach a state profile to hosts, and
+:ref:`that example <s4u_ex_comm_failure>` on how to react to networ failures.
+
+.. tabs::
+
+ .. example-tab:: examples/cpp/exec-failure/s4u-exec-failure.cpp
+
+.. _s4u_ex_dvfs:
+
+DVFS and pstates
+^^^^^^^^^^^^^^^^
+
+This example shows how to define a set of pstates in the XML. The current pstate
+of a host can then be accessed and changed from the program.
+
+.. tabs::
+
+ .. example-tab:: examples/cpp/exec-dvfs/s4u-exec-dvfs.cpp
+
+ See also :cpp:func:`simgrid::s4u::Host::get_pstate_speed` and :cpp:func:`simgrid::s4u::Host::set_pstate`.
+
+ .. example-tab:: examples/c/exec-dvfs/exec-dvfs.c
+
+ See also :cpp:func:`sg_host_get_pstate_speed` and :cpp:func:`sg_host_set_pstate`.
+
+ .. example-tab:: examples/python/exec-dvfs/exec-dvfs.py
+
+ See also :py:func:`simgrid.Host.pstate_speed()` and :py:attr:`simgrid.Host.pstate`.
+
+ .. example-tab:: examples/platforms/energy_platform.xml
+
+ The important parts are in the :ref:`pf_tag_host` tag. The ``pstate`` attribute is the initial pstate while the ``speed`` attribute must
+ be a comma-separated list of values: the speed at each pstate. This platform file also describes the ``wattage_per_state`` and
+ ``wattage_off`` properties, that are used by the :ref:`plugin_host_energy` plugin.