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