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