.. _S4U_doc:
-=================
The S4U Interface
-=================
+#################
.. raw:: html
<br/>
The S4U interface (SimGrid for you) mixes the full power of SimGrid
-with the full power of C++. This is the prefered interface to describe
-abstract algorithms in the domains of Cloud, P2P, HPC, IoT and similar
+with the full power of C++. This is the preferred interface to describe
+abstract algorithms in the domains of Cloud, P2P, HPC, IoT, and similar
settings.
--------------
+Currently (v3.21), S4U is definitely the way to go for long-term
+projects. It is feature complete, but may still evolve slightly in the
+future releases. It can already be used to do everything that can be
+done in SimGrid, but you may have to adapt your code in future
+releases. When this happens, compiling your code will produce
+deprecation warnings for 4 releases (one year) before the removal of
+the old symbols.
+If you want an API that will never ever evolve in the future, you
+should use the deprecated MSG API instead.
+
Main Concepts
--------------
+*************
A typical SimGrid simulation is composed of several |Actors|_, that
execute user-provided functions. The actors have to explicitly use the
-S4U interface to express their
-:ref:`computation <exhale_class_classsimgrid_1_1s4u_1_1Exec>`,
-:ref:`communication <exhale_class_classsimgrid_1_1s4u_1_1Comm>`,
-:ref:`disk usage <exhale_class_classsimgrid_1_1s4u_1_1Io>`,
+S4U interface to express their :ref:`computation <API_s4u_Exec>`,
+:ref:`communication <API_s4u_Comm>`, :ref:`disk usage <API_s4u_Io>`,
and other |Activities|_, so that they get reflected within the
simulator. These activities take place on resources such as |Hosts|_,
|Links|_ and |Storages|_. SimGrid predicts the time taken by each
-activity and orchestrates accordingly the actors waiting for the
+activity and orchestrates the actors accordingly, waiting for the
completion of these activities.
When **communicating**, data is not directly sent to other actors but
-posted onto a |Mailbox|_ that serve as rendez-vous point between
+posted onto a |Mailbox|_ that serves as a rendez-vous point between
communicating actors. This means that you don't need to know who you
are talking to, you just put your communication `Put` request in a
mailbox, and it will be matched with a complementary `Get`
resource to another. Each NetZone is included in another one, forming
a tree of NetZones which root zone contains the whole platform.
-The :ref:`simgrid::s4u::this_actor
-<namespace_simgrid__s4u__this_actor>` namespace provides many helper
-functions to simplify the code of actors.
+The :ref:`simgrid::s4u::this_actor <API_s4u_this_actor>` namespace
+provides many helper functions to simplify the code of actors.
- **Global Classes**
- - :ref:`class s4u::Actor <exhale_class_classsimgrid_1_1s4u_1_1Actor>`:
+ - :ref:`class s4u::Actor <API_s4u_Actor>`:
Active entities executing your application.
- - :ref:`class s4u::Engine <exhale_class_classsimgrid_1_1s4u_1_1Engine>`
+ - :ref:`class s4u::Engine <API_s4u_Engine>`
Simulation engine (singleton).
- - :ref:`class s4u::Mailbox <exhale_class_classsimgrid_1_1s4u_1_1Mailbox>`
+ - :ref:`class s4u::Mailbox <API_s4u_Mailbox>`
Communication rendez-vous.
- **Platform Elements**
- - :ref:`class s4u::Host <exhale_class_classsimgrid_1_1s4u_1_1Host>`:
+ - :ref:`class s4u::Host <API_s4u_Host>`:
Actor location, providing computational power.
- - :ref:`class s4u::Link <exhale_class_classsimgrid_1_1s4u_1_1Link>`
+ - :ref:`class s4u::Link <API_s4u_Link>`
Interconnecting hosts.
- - :ref:`class s4u::NetZone <exhale_class_classsimgrid_1_1s4u_1_1NetZone>`:
- Sub-region of the platform, containing resources (Hosts, Link, etc).
- - :ref:`class s4u::Storage <exhale_class_classsimgrid_1_1s4u_1_1Storage>`
+ - :ref:`class s4u::NetZone <API_s4u_NetZone>`:
+ Sub-region of the platform, containing resources (Hosts, Links, etc).
+ - :ref:`class s4u::Storage <API_s4u_Storage>`
Resource on which actors can write and read data.
- - :ref:`class s4u::VirtualMachine <exhale_class_classsimgrid_1_1s4u_1_1VirtualMachine>`:
+ - :ref:`class s4u::VirtualMachine <API_s4u_VirtualMachine>`:
Execution containers that can be moved between Hosts.
-- **Activities** (:ref:`class s4u::Activity <exhale_class_classsimgrid_1_1s4u_1_1Activity>`):
+- **Activities** (:ref:`class s4u::Activity <API_s4u_Activity>`):
The things that actors can do on resources
- - :ref:`class s4u::Comm <exhale_class_classsimgrid_1_1s4u_1_1Comm>`
+ - :ref:`class s4u::Comm <API_s4u_Comm>`
Communication activity, started on Mailboxes and consuming links.
- - :ref:`class s4u::Exec <exhale_class_classsimgrid_1_1s4u_1_1Exec>`
+ - :ref:`class s4u::Exec <API_s4u_Exec>`
Computation activity, started on Host and consuming CPU resources.
- - :ref:`class s4u::Io <exhale_class_classsimgrid_1_1s4u_1_1Io>`
+ - :ref:`class s4u::Io <API_s4u_Io>`
I/O activity, started on and consumming Storages.
- **Synchronization Mechanisms**: Classical IPC that actors can use
- - :ref:`class s4u::Barrier <exhale_class_classsimgrid_1_1s4u_1_1Barrier>`
- - :ref:`class s4u::ConditionVariable <exhale_class_classsimgrid_1_1s4u_1_1ConditionVariable>`
- - :ref:`class s4u::Mutex <exhale_class_classsimgrid_1_1s4u_1_1Mutex>`
- - :ref:`class s4u::Semaphore <exhale_class_classsimgrid_1_1s4u_1_1Semaphore>`
+ - :ref:`class s4u::Barrier <API_s4u_Barrier>`
+ - :ref:`class s4u::ConditionVariable <API_s4u_ConditionVariable>`
+ - :ref:`class s4u::Mutex <API_s4u_Mutex>`
+ - :ref:`class s4u::Semaphore <API_s4u_Semaphore>`
.. |Actors| replace:: **Actors**
.. |Mutex| replace:: **Mutex**
.. _Mutex: api/classsimgrid_1_1s4u_1_1Mutex.html
-----------
+.. THE EXAMPLES
+
+.. include:: ../../examples/s4u/README.rst
+
Activities
-----------
+**********
-Activities represent the actions that consumes a resource, such as
-:ref:`s4u::Comm <exhale_class_classsimgrid_1_1s4u_1_1Comm>` that
-consumes the *transmiting power* of :ref:`s4u::Link
-<exhale_class_classsimgrid_1_1s4u_1_1Link>` resources.
+Activities represent the actions that consume a resource, such as a
+:ref:`s4u::Comm <API_s4u_Comm>` that consumes the *transmiting power* of
+:ref:`s4u::Link <API_s4u_Link>` resources.
-.......................
+=======================
Asynchronous Activities
-.......................
+=======================
Every activity can be either **blocking** or **asynchronous**. For
example, :cpp:func:`s4u::Mailbox::put() <simgrid::s4u::Mailbox::put>`
completion of that communication. Asynchronous communications do not
block the actor during their execution but progress on their own.
-Once your asynchronous activity is started, you can test for
+Once your asynchronous activity is started, you can test for its
completion using :cpp:func:`s4u::Activity::test() <simgrid::s4u::Activity::test>`.
This function returns ``true`` if the activity completed already.
You can also use :cpp:func:`s4u::Activity::wait() <simgrid::s4u::Activity::wait>`
-to block until the completion of the activity. To wait at most for a given period,
+to block until the completion of the activity. To wait for at most a given amount of time,
use :cpp:func:`s4u::Activity::wait_for() <simgrid::s4u::Activity::wait_for>`.
Finally, to wait at most until a specified time limit, use
:cpp:func:`s4u::Activity::wait_until() <simgrid::s4u::Activity::wait_until>`.
Every kind of activities can be asynchronous:
- - :ref:`s4u::CommPtr <exhale_class_classsimgrid_1_1s4u_1_1Comm>` are created with
+ - :ref:`s4u::CommPtr <API_s4u_Comm>` are created with
:cpp:func:`s4u::Mailbox::put_async() <simgrid::s4u::Mailbox::put_async>` and
:cpp:func:`s4u::Mailbox::get_async() <simgrid::s4u::Mailbox::get_async>`.
- - :ref:`s4u::IoPtr <exhale_class_classsimgrid_1_1s4u_1_1Io>` are created with
+ - :ref:`s4u::IoPtr <API_s4u_Io>` are created with
:cpp:func:`s4u::Storage::read_async() <simgrid::s4u::Storage::read_async>` and
:cpp:func:`s4u::Storage::write_async() <simgrid::s4u::Storage::write_async>`.
- - :ref:`s4u::ExecPtr <exhale_class_classsimgrid_1_1s4u_1_1Exec>` are created with
+ - :ref:`s4u::ExecPtr <API_s4u_Exec>` are created with
:cpp:func:`s4u::Host::exec_async() <simgrid::s4u::Host::exec_async>`.
- In the future, it will become possible to have asynchronous IPC
such as asynchronous mutex lock requests.
:end-before: init-end
:dedent: 4
-You then start all communications that should occur concurrently with
+Then, you start all the communications that should occur concurrently with
:cpp:func:`s4u::Mailbox::put_async() <simgrid::s4u::Mailbox::put_async>`.
Finally, the actor waits for the completion of all of them at once
with
:dedent: 4
-.....................
+=====================
Activities Life cycle
-.....................
+=====================
Sometimes, you want to change the setting of an activity before it even starts.
+
+.. todo:: write this section
+
+Memory Management
+*****************
+
+For sake of simplicity, we use `RAII
+<https://en.wikipedia.org/wiki/Resource_Acquisition_Is_Initialization>`_
+everywhere in S4U. This is an idiom where resources are automatically
+managed through the context. Provided that you never manipulate
+objects of type Foo directly but always FooPtr references (which are
+defined as `boost::intrusive_ptr
+<http://www.boost.org/doc/libs/1_61_0/libs/smart_ptr/intrusive_ptr.html>`_
+<Foo>), you will never have to explicitely release the resource that
+you use nor to free the memory of unused objects.
+
+Here is a little example:
+
+.. code-block:: cpp
+
+ void myFunc()
+ {
+ simgrid::s4u::MutexPtr mutex = simgrid::s4u::Mutex::create(); // Too bad we cannot use `new`
+
+ mutex->lock(); // use the mutex as a simple reference
+ // bla bla
+ mutex->unlock();
+
+ } // The mutex gets automatically freed because the only existing reference gets out of scope
+
+API Reference
+*************
+
+.. _API_s4u_Activity:
+
+=============
+s4u::Activity
+=============
+
+.. doxygenclass:: simgrid::s4u::Activity
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Actor:
+
+==========
+s4u::Actor
+==========
+
+.. doxygentypedef:: ActorPtr
+
+.. doxygenclass:: simgrid::s4u::Actor
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Barrier:
+
+============
+s4u::Barrier
+============
+
+.. doxygentypedef:: BarrierPtr
+
+.. doxygenclass:: simgrid::s4u::Barrier
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Comm:
+
+=========
+s4u::Comm
+=========
+
+.. doxygentypedef:: CommPtr
+
+.. doxygenclass:: simgrid::s4u::Comm
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_ConditionVariable:
+
+======================
+s4u::ConditionVariable
+======================
+
+.. doxygentypedef:: ConditionVariablePtr
+
+.. doxygenclass:: simgrid::s4u::ConditionVariable
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Engine:
+
+===========
+s4u::Engine
+===========
+
+.. doxygenclass:: simgrid::s4u::Engine
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Exec:
+
+=========
+s4u::Exec
+=========
+
+.. doxygentypedef:: ExecPtr
+
+.. doxygenclass:: simgrid::s4u::Exec
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Host:
+
+=========
+s4u::Host
+=========
+
+.. doxygenclass:: simgrid::s4u::Host
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Io:
+
+=======
+s4u::Io
+=======
+
+.. doxygentypedef:: IoPtr
+
+.. doxygenclass:: simgrid::s4u::Io
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Link:
+
+=========
+s4u::Link
+=========
+
+.. doxygenclass:: simgrid::s4u::Link
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Mailbox:
+
+============
+s4u::Mailbox
+============
+
+.. doxygentypedef:: MailboxPtr
+
+.. doxygenclass:: simgrid::s4u::Mailbox
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Mutex:
+
+==========
+s4u::Mutex
+==========
+
+.. doxygentypedef:: MutexPtr
+
+.. doxygenclass:: simgrid::s4u::Mutex
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_NetZone:
+
+============
+s4u::NetZone
+============
+
+.. doxygenclass:: simgrid::s4u::NetZone
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Semaphore:
+
+==============
+s4u::Semaphore
+==============
+
+.. doxygentypedef:: SemaphorePtr
+
+.. doxygenclass:: simgrid::s4u::Semaphore
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_Storage:
+
+============
+s4u::Storage
+============
+
+.. doxygenclass:: simgrid::s4u::Storage
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_VirtualMachine:
+
+===================
+s4u::VirtualMachine
+===================
+
+.. doxygenclass:: simgrid::s4u::VirtualMachine
+ :members:
+ :protected-members:
+ :undoc-members:
+
+.. _API_s4u_this_actor:
+
+=========================
+namespace s4u::this_actor
+=========================
+
+
+.. doxygennamespace:: simgrid::s4u::this_actor
