examples/s4u/README.rst

   1 .. S4U (Simgrid for you) is the next interface of SimGrid, expected to be released with SimGrid 4.0.
   2 ..
   3 .. Even if it is not completely rock stable yet, it may well already fit
   4 .. your needs. You are welcome to try it and report any interface
   5 .. glitches that you see. Be however warned that the interface may change
   6 .. until the final release.  You will have to adapt your code on the way.
   7 ..
   8 .. This file follows the ReStructured syntax to be included in the
   9 .. documentation, but it should remain readable directly.
  10
  11
  12 S4U Examples
  13 ************
  14
  15 SimGrid comes with an extensive set of examples, documented on this
  16 page. Most of them only demonstrate one single feature, with some
  17 larger examplars listed below.
  18
  19 The C++ examples can be found under examples/s4u while python examples
  20 are in examples/python. Each such directory contains the source code (also listed
  21 from this page), and the so-called tesh file containing how to call
  22 the binary obtained by compiling this example and also the expected
  23 output. Tesh files are used to turn each of our examples into an
  24 integration test. Some examples also contain other files, on need.
  25
  26 A good way to bootstrap your own project is to copy and combine some
  27 of the provided examples to constitute the skeleton of what you plan
  28 to simulate.
  29
  30 ===========================
  31 Actors: the Active Entities
  32 ===========================
  33
  34 .. _s4u_ex_actors:
  35
  36 Starting and Stoping Actors
  37 ---------------------------
  38
  39   - **Creating actors:**
  40     Most actors are started from the deployment XML file, but there is other methods.
  41     This example show them all.
  42     `examples/python/actor-create/actor-create_d.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/python/actor-create/actor-create_d.xml>`_
  43
  44     - |cpp| `examples/s4u/actor-create/s4u-actor-create.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-create/s4u-actor-create.cpp>`_
  45     - |py|  `examples/python/actor-create/actor-create.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/actor-create/actor-create.py>`_
  46
  47   - **React to the end of actors:**
  48     You can attach a callback to the end of actors. There is two ways
  49     of doing so, depending of whether you want your callback to be
  50     executed when a specific actor ends (with ```this_actor::on_exit()```)
  51     or whether it should be executed when any actor ends (with
  52     ```Actor::on_termination()```) or when it gets destroyed (with
  53     ```Actor::on_destruction()```)
  54
  55     - |cpp| `examples/s4u/actor-exiting/s4u-actor-exiting.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-exiting/s4u-actor-exiting.cpp>`_
  56
  57   - **Kill actors:**
  58     Actors can forcefully stop other actors.
  59
  60     - |cpp| `examples/s4u/actor-kill/s4u-actor-kill.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-kill/s4u-actor-kill.cpp>`_
  61       :cpp:func:`void simgrid::s4u::Actor::kill(void)`,
  62       :cpp:func:`void simgrid::s4u::Actor::kill_all()`,
  63       :cpp:func:`simgrid::s4u::this_actor::exit`.
  64     - |py| `examples/python/actor-kill/actor-kill.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/actor-kill/actor-kill.py>`_
  65       :py:func:`simgrid.Actor.kill`,
  66       :py:func:`simgrid.Actor.kill_all`,
  67       :py:func:`simgrid.this_actor.exit`.
  68
  69   - **Controling the actor life cycle from the XML:**
  70     You can specify a start time and a kill time in the deployment
  71     file.
  72     |br| `examples/s4u/actor-lifetime/s4u-actor-lifetime.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-lifetime/s4u-actor-lifetime.cpp>`_
  73     |br| `examples/s4u/actor-lifetime/s4u-actor-lifetime_d.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-lifetime/s4u-actor-lifetime_d.xml>`_
  74
  75   - **Daemonize actors:**
  76     Some actors may be intended to simulate daemons that run in background. This example show how to transform a regular
  77     actor into a daemon that will be automatically killed once the simulation is over.
  78
  79     - |cpp| `examples/s4u/actor-daemon/s4u-actor-daemon.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-daemon/s4u-actor-daemon.cpp>`_
  80     - |py|  `examples/python/actor-daemon/actor-daemon.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/actor-daemon/actor-daemon.py>`_
  81
  82 Inter-Actors Interactions
  83 -------------------------
  84
  85 See also the examples on :ref:`inter-actors communications
  86 <s4u_ex_communication>` and the ones on :ref:`classical
  87 synchronization objects <s4u_ex_IPC>`.
  88
  89   - **Suspend and Resume actors:**
  90     Actors can be suspended and resumed during their executions.
  91
  92     - |cpp| `examples/s4u/actor-suspend/s4u-actor-suspend.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-suspend/s4u-actor-suspend.cpp>`_
  93       :cpp:func:`simgrid::s4u::this_actor::suspend()`,
  94       :cpp:func:`simgrid::s4u::Actor::suspend()`, :cpp:func:`simgrid::s4u::Actor::resume()`, :cpp:func:`simgrid::s4u::Actor::is_suspended()`.
  95     - |py|  `examples/python/actor-suspend/actor-suspend.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/actor-suspend/actor-suspend.py>`_
  96       :py:func:`simgrid.this_actor.suspend()`,
  97       :py:func:`simgrid.Actor.suspend()`, :py:func:`simgrid.Actor.resume()`, :py:func:`simgrid.Actor.is_suspended()`.
  98
  99   - **Migrating Actors:**
 100     Actors can move or be moved from a host to another very easily.
 101
 102     - |cpp| `examples/s4u/actor-migrate/s4u-actor-migrate.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-migrate/s4u-actor-migrate.cpp>`_
 103       :cpp:func:`simgrid::s4u::this_actor::migrate()`
 104     - |py|  `examples/python/actor-migrate/actor-migrate.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/actor-migrate/actor-migrate.py>`_
 105       :py:func:`simgrid.this_actor.migrate()`
 106
 107   - **Waiting for the termination of an actor:** (joining on it)
 108     You can block the current actor until the end of another actor.
 109
 110     - |cpp| `examples/s4u/actor-join/s4u-actor-join.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-join/s4u-actor-join.cpp>`_
 111       :cpp:func:`simgrid::s4u::Actor::join()`
 112     - |py|  `examples/python/actor-join/actor-join.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/actor-join/actor-join.py>`_
 113       :py:func:`simgrid.Actor.join()`
 114
 115   - **Yielding to other actors**.
 116     The ```yield()``` function interrupts the execution of the current
 117     actor, leaving a chance to the other actors that are ready to run
 118     at this timestamp.
 119
 120     - |cpp| `examples/s4u/actor-yield/s4u-actor-yield.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-yield/s4u-actor-yield.cpp>`_
 121       :cpp:func:`simgrid::s4u::this_actor::yield()`
 122     - |py|  `examples/python/actor-yield/actor-yield.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/actor-yield/actor-yield.py>`_
 123       :py:func:`simgrid.this_actor.yield_()`
 124
 125 Traces Replay as a Workload
 126 ---------------------------
 127
 128 This section details how to run trace-driven simulations. It is very
 129 handy when you want to test an algorithm or protocol that only react
 130 to external events. For example, many P2P protocols react to user
 131 requests, but do nothing if there is no such event.
 132
 133 In such situations, you should write your protocol in C++, and separate
 134 the workload that you want to play onto your protocol in a separate
 135 text file. Declare a function handling each type of the events in your
 136 trace, register them using :cpp:func:`xbt_replay_action_register()` in
 137 your main, and then run the simulation.
 138
 139 Then, you can either have one trace file containing all your events,
 140 or a file per simulated process: the former may be easier to work
 141 with, but the second is more efficient on very large traces. Check
 142 also the tesh files in the example directories for details.
 143
 144   - **Communication replay:**
 145     Presents a set of event handlers reproducing classical communication
 146     primitives (asynchronous send/receive at the moment).
 147     |br| `examples/s4u/replay-comm/s4u-replay-comm.cpp  <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/replay-comm/s4u-replay-comm.cpp>`_
 148
 149   - **I/O replay:**
 150     Presents a set of event handlers reproducing classical I/O
 151     primitives (open, read, close).
 152     |br| `examples/s4u/replay-storage/s4u-replay-storage.cpp  <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/replay-storage/s4u-replay-storage.cpp>`_
 153
 154 ==========================
 155 Activities: what Actors do
 156 ==========================
 157
 158 .. _s4u_ex_communication:
 159
 160 Communications on the Network
 161 -----------------------------
 162
 163  - **Basic asynchronous communications:**
 164    Illustrates how to have non-blocking communications, that are
 165    communications running in the background leaving the process free
 166    to do something else during their completion.
 167
 168    - |cpp| `examples/s4u/async-wait/s4u-async-wait.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/async-wait/s4u-async-wait.cpp>`_
 169      :cpp:func:`simgrid::s4u::Mailbox::put_async()` and :cpp:func:`simgrid::s4u::Comm::wait()`
 170    - |py|  `examples/python/async-wait/async-wait.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/async-wait/async-wait.py>`_
 171      :py:func:`simgrid.Mailbox.put_async()` :py:func:`simgrid.Comm.wait()`
 172
 173  - **Waiting for all communications in a set:**
 174    The `wait_all()` function is useful when you want to block until
 175    all activities in a given set have completed.
 176
 177    - |cpp| `examples/s4u/async-waitall/s4u-async-waitall.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/async-waitall/s4u-async-waitall.cpp>`_
 178      :cpp:func:`simgrid::s4u::Comm::wait_all()`
 179    - |py| `examples/python/async-waitall/async-waitall.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/async-waitall/async-waitall.py>`_
 180      :py:func:`simgrid.Comm.wait_all()`
 181
 182  - **Waiting for the first completed communication in a set:**
 183    The `wait_any()` function is useful
 184    when you want to block until one activity of the set completes, no
 185    matter which terminates first.
 186
 187    - |cpp| `examples/s4u/async-waitany/s4u-async-waitany.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/async-waitany/s4u-async-waitany.cpp>`_
 188      :cpp:func:`simgrid::s4u::Comm::wait_any()`
 189    - |py| `examples/python/async-waitany/async-waitany.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/async-waitany/async-waitany.py>`_
 190      :py:func:`simgrid.Comm.wait_any()`
 191
 192 .. todo:: review the `ready` and `waituntil` examples and add them here.
 193
 194 .. _s4u_ex_execution:
 195
 196 Executions on the CPU
 197 ---------------------
 198
 199   - **Basic execution:**
 200     The computations done in your program are not reported to the
 201     simulated world, unless you explicitely request the simulator to pause
 202     the actor until a given amount of flops gets computed on its simulated
 203     host. Some executions can be given an higher priority so that they
 204     get more resources.
 205
 206     - |cpp| `examples/s4u/exec-basic/s4u-exec-basic.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-basic/s4u-exec-basic.cpp>`_
 207     - |py|  `examples/python/exec-basic/exec-basic.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/exec-basic/exec-basic.py>`_
 208
 209   - **Asynchronous execution:**
 210     You can start asynchronous executions, just like you would fire
 211     background threads.
 212
 213     - |cpp| `examples/s4u/exec-async/s4u-exec-async.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-async/s4u-exec-async.cpp>`_
 214     - |py|  `examples/python/exec-async/exec-async.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/exec-async/exec-async.py>`_
 215
 216   - **Remote execution:**
 217     You can start executions on remote hosts, or even change the host
 218     on which they occur during their execution.
 219
 220     - |cpp| `examples/s4u/exec-remote/s4u-exec-remote.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-remote/s4u-exec-remote.cpp>`_
 221     - |py| `examples/python/exec-remote/exec-remote.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/exec-remote/exec-remote.py>`_
 222
 223   - **Parallel executions:**
 224     These objects are convenient abstractions of parallel
 225     computational kernels that span over several machines, such as a
 226     PDGEM and the other ScaLAPACK routines. Note that this only works
 227     with the "ptask_L07" host model (``--cfg=host/model:ptask_L07``).
 228     |br| `examples/s4u/exec-ptask/s4u-exec-ptask.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-ptask/s4u-exec-ptask.cpp>`_
 229
 230   - **Using Pstates on a host:**
 231     `examples/platforms/energy_platform.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms/energy_platform.xml>`_
 232     shows how define a set of pstates in the XML. The current pstate
 233     of an host can then be accessed and changed from the program.
 234
 235     - |cpp| `examples/s4u/exec-dvfs/s4u-exec-dvfs.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-dvfs/s4u-exec-dvfs.cpp>`_
 236       :cpp:func:`simgrid::s4u::Host::get_pstate_speed` and :cpp:func:`simgrid::s4u::Host::set_pstate`.
 237     - |py|  `examples/python/exec-dvfs/exec-dvfs.py <https://framagit.org/simgrid/simgrid/tree/master/examples/python/exec-dvfs/exec-dvfs.py>`_
 238       :py:func:`Host.get_pstate_speed` and :py:func:`Host.set_pstate`.
 239
 240 I/O on Disks and Files
 241 ----------------------
 242
 243 SimGrid provides two levels of abstraction to interact with the
 244 simulated storages. At the simplest level, you simply create read and
 245 write actions on the storage resources.
 246
 247   - **Access to raw storage devices:**
 248     This example illustrates how to simply read and write data on a
 249     simulated storage resource.
 250     |br| `examples/s4u/io-storage-raw/s4u-io-storage-raw.cpp  <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/io-storage-raw/s4u-io-storage-raw.cpp>`_
 251
 252 The FileSystem plugin provides a more detailed view, with the
 253 classical operations over files: open, move, unlink, and of course
 254 read and write. The file and disk sizes are also dealt with and can
 255 result in short reads and short write, as in reality.
 256
 257   - **File Management:**
 258     This example illustrates the use of operations on files
 259     (read, write, seek, tell, unlink, etc).
 260     |br| `examples/s4u/io-file-system/s4u-io-file-system.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/io-file-system/s4u-io-file-system.cpp>`_
 261
 262   - **Remote I/O:**
 263     I/O operations on files can also be done in a remote fashion,
 264     i.e. when the accessed disk is not mounted on the caller's host.
 265     |br| `examples/s4u/io-file-remote/s4u-io-file-remote.cpp  <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/io-file-remote/s4u-io-file-remote.cpp>`_
 266
 267 .. _s4u_ex_IPC:
 268
 269 Classical synchronization objects
 270 ---------------------------------
 271
 272  - **Mutex:**
 273    Shows how to use simgrid::s4u::Mutex synchronization objects.
 274    |br| `examples/s4u/synchro-mutex/s4u-synchro-mutex.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/synchro-mutex/s4u-synchro-mutex.cpp>`_
 275
 276  - **Barrier:**
 277    Shows how to use simgrid::s4u::Barrier synchronization objects.
 278    |br| `examples/s4u/synchro-barrier/s4u-synchro-barrier.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/synchro-barrier/s4u-synchro-barrier.cpp>`_
 279
 280  - **Semaphore:**
 281    Shows how to use simgrid::s4u::Semaphore synchronization objects.
 282    |br| `examples/s4u/synchro-semaphore/s4u-synchro-semaphore.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/synchro-semaphore/s4u-synchro-semaphore.cpp>`_
 283
 284 =============================
 285 Interacting with the Platform
 286 =============================
 287
 288  - **Retrieving the list of hosts matching a given criteria:**
 289    Shows how to filter the actors that match a given criteria.
 290    |br| `examples/s4u/engine-filtering/s4u-engine-filtering.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/engine-filtering/s4u-engine-filtering.cpp>`_
 291
 292  - **User-defined properties:**
 293    You can attach arbitrary information to most platform elements from
 294    the XML file, and then interact with these values from your
 295    program. Note that the changes are not written permanently on disk,
 296    in the XML file nor anywhere else. They only last until the end of
 297    your simulation.
 298
 299    - :cpp:func:`simgrid::s4u::Actor::get_property()` and :cpp:func:`simgrid::s4u::Actor::set_property()`
 300    - :cpp:func:`simgrid::s4u::Host::get_property()` and :cpp:func:`simgrid::s4u::Host::set_property()`
 301    - :cpp:func:`simgrid::s4u::Link::get_property()` and :cpp:func:`simgrid::s4u::Link::set_property()`
 302    - :cpp:func:`simgrid::s4u::NetZone::get_property()` and :cpp:func:`simgrid::s4u::NetZone::set_property()`
 303
 304    |br| `examples/s4u/platform-properties/s4u-platform-properties.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/platform-properties/s4u-platform-properties.cpp>`_
 305    |br| `examples/s4u/platform-properties/s4u-platform-properties_d.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/platform-properties/s4u-platform-properties_d.xml>`_
 306    |br| `examples/platforms/prop.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms/prop.xml>`_
 307
 308  - **Specifying state profiles:** shows how to specify when the
 309    resources must be turned off and on again, and how to react to such
 310    failures in your code.
 311
 312    |br| `examples/platforms/small_platform_failures.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms/small_platform_failures.xml>`_
 313    |br| The state profiles in `examples/platforms/profiles <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms/profiles>`_
 314
 315  - **Specifying speed profiles:** shows how to specify an external
 316    load to resources, variating their peak speed over time.
 317
 318    |br| `examples/platforms/small_platform_profile.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms/small_platform_profile.xml>`_
 319    |br| The speed, bandwidth and latency profiles in `examples/platforms/profiles  <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms/profiles>`_
 320
 321 =================
 322 Energy Simulation
 323 =================
 324
 325   - **Describing the energy profiles in the platform:**
 326     This platform file contains the energy profile of each links and
 327     hosts, which is necessary to get energy consumption predictions.
 328     As usual, you should not trust our example, and you should strive
 329     to double-check that your instanciation matches your target platform.
 330     |br| `examples/platforms/energy_platform.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms/energy_platform.xml>`_
 331
 332   - **Consumption due to the CPU:**
 333     This example shows how to retrieve the amount of energy consumed
 334     by the CPU during computations, and the impact of the pstate.
 335     |br| `examples/s4u/energy-exec/s4u-energy-exec.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/energy-exec/s4u-energy-exec.cpp>`_
 336
 337   - **Consumption due to the network:**
 338     This example shows how to retrieve and display the energy consumed
 339     by the network during communications.
 340     |br| `examples/s4u/energy-link/s4u-energy-link.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/energy-link/s4u-energy-link.cpp>`_
 341
 342   - **Modeling the shutdown and boot of hosts:**
 343     Simple example of model of model for the energy consumption during
 344     the host boot and shutdown periods.
 345     |br| `examples/s4u/energy-boot/platform_boot.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/energy-boot/platform_boot.xml>`_
 346     |br| `examples/s4u/energy-boot/s4u-energy-boot.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/energy-boot/s4u-energy-boot.cpp>`_
 347
 348 =======================
 349 Tracing and Visualizing
 350 =======================
 351
 352 Tracing can be activated by various configuration options which
 353 are illustrated in these example. See also the
 354 :ref:`full list of options related to tracing <tracing_tracing_options>`.
 355
 356 It is interesting to run the process-create example with the following
 357 options to see the task executions:
 358
 359   - **Platform Tracing:**
 360     This program is a toy example just loading the platform, so that
 361     you can play with the platform visualization. Recommanded options:
 362     ``--cfg=tracing:yes --cfg=tracing/categorized:yes``
 363     |br| `examples/s4u/trace-platform/s4u-trace-platform.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/trace-platform/s4u-trace-platform.cpp>`_
 364
 365 ========================
 366 Larger SimGrid Examplars
 367 ========================
 368
 369 This section contains application examples that are somewhat larger
 370 than the previous examples.
 371
 372   - **Ping Pong:**
 373     This simple example just sends one message back and forth.
 374     The tesh file laying in the directory show how to start the simulator binary, highlighting how to pass options to
 375     the simulators (as detailed in Section :ref:`options`).
 376     |br| `examples/s4u/app-pingpong/s4u-app-pingpong.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/app-pingpong/s4u-app-pingpong.cpp>`_
 377
 378   - **Token ring:**
 379     Shows how to implement a classical communication pattern, where a
 380     token is exchanged along a ring to reach every participant.
 381     |br| `examples/s4u/app-token-ring/s4u-app-token-ring.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/app-token-ring/s4u-app-token-ring.cpp>`_
 382
 383   - **Master Workers:**
 384     Another good old example, where one Master process has a bunch of task to dispatch to a set of several Worker
 385     processes. This example comes in two equivalent variants, one
 386     where the actors are specified as simple functions (which is easier to
 387     understand for newcomers) and one where the actors are specified
 388     as classes (which is more powerful for the users wanting to build
 389     their own projects upon the example).
 390     |br| `examples/s4u/app-masterworkers/s4u-app-masterworkers-class.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/app-masterworkers/s4u-app-masterworkers-class.cpp>`_
 391     |br| `examples/s4u/app-masterworkers/s4u-app-masterworkers-fun.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/app-masterworkers/s4u-app-masterworkers-fun.cpp>`_
 392
 393 Data diffusion
 394 --------------
 395
 396   - **Bit Torrent:**
 397     Classical protocol for Peer-to-Peer data diffusion.
 398     |br| `examples/s4u/app-bittorrent/s4u-bittorrent.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/app-bittorrent/s4u-bittorrent.cpp>`_
 399
 400   - **Chained Send:**
 401     Data broadcast over a ring of processes.
 402     |br| `examples/s4u/app-chainsend/s4u-app-chainsend.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/app-chainsend/s4u-app-chainsend.cpp>`_
 403
 404 Distributed Hash Tables (DHT)
 405 -----------------------------
 406
 407   - **Chord Protocol**
 408     One of the most famous DHT protocol.
 409     |br| `examples/s4u/dht-chord/s4u-dht-chord.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/dht-chord/s4u-dht-chord.cpp>`_
 410
 411 .. _s4u_ex_clouds:
 412
 413 Simulating Clouds
 414 -----------------
 415
 416   - **Cloud basics**
 417     This example starts some computations both on PMs and VMs, and
 418     migrates some VMs around.
 419     |br| `examples/s4u/cloud-simple/s4u-cloud-simple.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/cloud-simple/s4u-cloud-simple.cpp>`_
 420
 421 .. TODO:: document here the examples about clouds and plugins
 422
 423 =======================
 424 Model-Checking Examples
 425 =======================
 426
 427 The model-checker can be used to exhaustively search for issues in the
 428 tested application. It must be activated at compile time, but this
 429 mode is rather experimental in SimGrid (as of v3.22). You should not
 430 enable it unless you really want to formally verify your applications:
 431 SimGrid is slower and maybe less robust when MC is enabled.
 432
 433   - **Failing assert**
 434     In this example, two actors send some data to a central server,
 435     which asserts that the messages are always received in the same order.
 436     This is obviously wrong, and the model-checker correctly finds a
 437     counter-example to that assertion.
 438     |br| `examples/s4u/mc-failing-assert/s4u-mc-failing-assert.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/mc-failing-assert/s4u-mc-failing-assert.cpp>`_
 439
 440 .. |br| raw:: html
 441
 442    <br />
 443
 444 .. |cpp| image:: /img/lang_cpp.png
 445    :align: middle
 446    :width: 12
 447
 448 .. |py| image:: /img/lang_python.png
 449    :align: middle
 450    :width: 12