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