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 ------------
  13 S4U Examples
  14 ------------
  15
  16 SimGrid comes with an extensive set of examples, documented on this
  17 page. Most of them only demonstrate one single feature, with some
  18 larger examplars listed below.
  19
  20 Each of these examples can be found in a subdirectory under
  21 examples/s4u in the archive. It contains the source code (also listed
  22 from this page), and the so-called tesh file containing how to call
  23 the binary obtained by compiling this example and also the expected
  24 output. Tesh files are used to turn each of our examples into an
  25 integration test. Some examples also contain other files, on need.
  26
  27 A good way to bootstrap your own project is to copy and combine some
  28 of the provided examples to constitute the skeleton of what you plan
  29 to simulate.
  30
  31 ...........................
  32 Actors: the Active Entities
  33 ...........................
  34
  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     |br| `examples/s4u/actor-create/s4u-actor-create.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-create/s4u-actor-create.cpp>`_
  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| `examples/s4u/actor-daemon/s4u-actor-daemon.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-daemon/s4u-actor-daemon.cpp>`_
  60
  61 Inter-Actors Interactions
  62 ^^^^^^^^^^^^^^^^^^^^^^^^^
  63
  64   - **Suspend and Resume actors:**
  65     Actors can be suspended and resumed during their executions thanks
  66     to :cpp:func:`simgrid::s4u::Actor::suspend()` and
  67     :cpp:func:`simgrid::s4u::Actor::resume()`.
  68     |br| `examples/s4u/actor-suspend/s4u-actor-suspend.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-suspend/s4u-actor-suspend.cpp>`_
  69
  70   - **Migrating Actors:**
  71     Actors can move or be moved from a host to another with
  72     :cpp:func:`simgrid::s4u::this_actor::migrate()`.
  73     |br| `examples/s4u/actor-migration/s4u-actor-migration.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-migration/s4u-actor-migration.cpp>`_
  74
  75   - **Waiting for the termination of an actor:** (joining on it)
  76     :cpp:func:`simgrid::s4u::Actor::join()` allows to block the current
  77     actor until the end of the receiving actor.
  78     |br| `examples/s4u/actor-join/s4u-actor-join.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-join/s4u-actor-join.cpp>`_
  79
  80   - **Yielding to other actor**.
  81     The :cpp:func:`simgrid::s4u::this_actor::yield()` function interrupts the
  82     execution of the current actor, leaving a chance to the other actors
  83     that are ready to run at this timestamp.
  84     |br| `examples/s4u/actor-yield/s4u-actor-yield.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/actor-yield/s4u-actor-yield.cpp>`_
  85
  86 Traces Replay as a Workload
  87 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  88
  89 This section details how to run trace-driven simulations. It is very
  90 handy when you want to test an algorithm or protocol that only react
  91 to external events. For example, many P2P protocols react to user
  92 requests, but do nothing if there is no such event.
  93
  94 In such situations, you should write your protocol in C++, and separate
  95 the workload that you want to play onto your protocol in a separate
  96 text file. Declare a function handling each type of the events in your
  97 trace, register them using :cpp:func:`xbt_replay_action_register()` in
  98 your main, and then run the simulation.
  99
 100 Then, you can either have one trace file containing all your events,
 101 or a file per simulated process: the former may be easier to work
 102 with, but the second is more efficient on very large traces. Check
 103 also the tesh files in the example directories for details.
 104
 105   - **Communication replay:**
 106     Presents a set of event handlers reproducing classical communication
 107     primitives (asynchronous send/receive at the moment).
 108     |br| `examples/s4u/replay-comm/s4u-replay-comm.cpp  <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/replay-comm/s4u-replay-comm.cpp>`_
 109
 110   - **I/O replay:**
 111     Presents a set of event handlers reproducing classical I/O
 112     primitives (open, read, close).
 113     |br| `examples/s4u/replay-storage/s4u-replay-storage.cpp  <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/replay-storage/s4u-replay-storage.cpp>`_
 114
 115 ..........................
 116 Activities: what Actors do
 117 ..........................
 118
 119 Communications on the Network
 120 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 121
 122  - **Basic asynchronous communications:**
 123    Illustrates how to have non-blocking communications, that are
 124    communications running in the background leaving the process free
 125    to do something else during their completion. The main functions
 126    involved are :cpp:func:`simgrid::s4u::Mailbox::put_async()` and
 127    :cpp:func:`simgrid::s4u::Comm::wait()`.
 128    |br| `examples/s4u/async-wait/s4u-async-wait.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/async-wait/s4u-async-wait.cpp>`_
 129
 130  - **Waiting for all communications in a set:**
 131    The :cpp:func:`simgrid::s4u::Comm::wait_all()` function is useful
 132    when you want to block until all activities in a given set have
 133    completed.
 134    |br| `examples/s4u/async-waitall/s4u-async-waitall.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/async-waitall/s4u-async-waitall.cpp>`_
 135
 136  - **Waiting for the first completed communication in a set:**
 137    The :cpp:func:`simgrid::s4u::Comm::wait_any()` function is useful
 138    when you want to block until one activity of the set completes, no
 139    matter which terminates first.
 140    |br| `examples/s4u/async-waitany/s4u-async-waitany.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/async-waitany/s4u-async-waitany.cpp>`_
 141
 142 .. todo:: add the `ready` example here
 143
 144 Executions on the CPU
 145 ^^^^^^^^^^^^^^^^^^^^^
 146
 147   - **Basic execution:**
 148     The computations done in your program are not reported to the
 149     simulated world, unless you explicitely request the simulator to pause
 150     the actor until a given amount of flops gets computed on its simulated
 151     host. Some executions can be given an higher priority so that they
 152     get more resources.
 153     |br| `examples/s4u/exec-basic/s4u-exec-basic.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-basic/s4u-exec-basic.cpp>`_
 154
 155   - **Asynchronous execution:**
 156     You can start asynchronous executions, just like you would fire
 157     background threads.
 158     |br| `examples/s4u/exec-async/s4u-exec-async.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-async/s4u-exec-async.cpp>`_
 159
 160   - **Monitoring asynchronous executions:**
 161     This example shows how to start an asynchronous execution, and
 162     monitor its status.
 163     |br| `examples/s4u/exec-monitor/s4u-exec-monitor.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-monitor/s4u-exec-monitor.cpp>`_
 164
 165   - **Remote execution:**
 166     Before its start, you can change the host on which a given execution will occur.
 167     |br| `examples/s4u/exec-remote/s4u-exec-remote.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-remote/s4u-exec-remote.cpp>`_
 168
 169   - **Using Pstates on a host:**
 170     Shows how define a set of pstatesfor a host in the XML, and how the current
 171     pstate can be accessed/changed with :cpp:func:`simgrid::s4u::Host::get_pstate_speed` and :cpp:func:`simgrid::s4u::Host::set_pstate`.
 172     |br| `examples/s4u/exec-dvfs/s4u-exec-dvfs.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-dvfs/s4u-exec-dvfs.cpp>`_
 173     |br| `examples/platforms/energy_platform.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms/energy_platform.xml>`_
 174
 175   - **Parallel tasks:**
 176     These objects are convenient abstractions of parallel
 177     computational kernels that span over several machines.
 178     |br| `examples/s4u/exec-ptask/s4u-exec-ptask.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/exec-ptask/s4u-exec-ptask.cpp>`_
 179
 180 I/O on Disks and Files
 181 ^^^^^^^^^^^^^^^^^^^^^^
 182
 183 SimGrid provides two levels of abstraction to interact with the
 184 simulated storages. At the simplest level, you simply create read and
 185 write actions on the storage resources.
 186
 187   - **Access to raw storage devices:**
 188     This example illustrates how to simply read and write data on a
 189     simulated storage resource.
 190     |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>`_
 191
 192 The FileSystem plugin provides a more detailed view, with the
 193 classical operations over files: open, move, unlink, and of course
 194 read and write. The file and disk sizes are also dealt with and can
 195 result in short reads and short write, as in reality.
 196
 197   - **File Management:**
 198     This example illustrates the use of operations on files
 199     (read, write, seek, tell, unlink, etc).
 200     |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>`_
 201
 202   - **Remote I/O:**
 203     I/O operations on files can also be done in a remote fashion,
 204     i.e. when the accessed disk is not mounted on the caller's host.
 205     |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>`_
 206
 207 Classical synchronization objects
 208 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 209
 210  - **Mutex:**
 211    Shows how to use simgrid::s4u::Mutex synchronization objects.
 212    |br| `examples/s4u/synchro-mutex/s4u-synchro-mutex.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/synchro-mutex/s4u-synchro-mutex.cpp>`_
 213
 214  - **Barrier:**
 215    Shows how to use simgrid::s4u::Barrier synchronization objects.
 216    |br| `examples/s4u/synchro-barrier/s4u-synchro-barrier.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/synchro-barrier/s4u-synchro-barrier.cpp>`_
 217
 218 .............................
 219 Interacting with the platform
 220 .............................
 221
 222  - **Retrieving the list of hosts matching a given criteria:**
 223    Shows how to filter the actors that match a given criteria.
 224    |br| `examples/s4u/engine-filtering/s4u-engine-filtering.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/engine-filtering/s4u-engine-filtering.cpp>`_
 225
 226  - **User-defined properties:**
 227    You can attach arbitrary information to most platform elements from
 228    the XML file, and then interact with these values from your
 229    program. Note that the changes are not written permanently on disk,
 230    in the XML file nor anywhere else. They only last until the end of
 231    your simulation.
 232
 233    - :cpp:func:`simgrid::s4u::Actor::get_property()` and :cpp:func:`simgrid::s4u::Actor::set_property()`
 234    - :cpp:func:`simgrid::s4u::Host::get_property()` and :cpp:func:`simgrid::s4u::Host::set_property()`
 235    - :cpp:func:`simgrid::s4u::Link::get_property()` and :cpp:func:`simgrid::s4u::Link::set_property()`
 236    - :cpp:func:`simgrid::s4u::NetZone::get_property()` and :cpp:func:`simgrid::s4u::NetZone::set_property()`
 237
 238    |br| `examples/s4u/platform-properties/s4u-platform-properties.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/platform-properties/s4u-platform-properties.cpp>`_
 239    |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>`_
 240    |br| `examples/platforms/prop.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms/prop.xml>`_
 241
 242 .................
 243 Energy Simulation
 244 .................
 245
 246   - **Describing the energy profiles in the platform:**
 247     This platform file contains the energy profile of each links and
 248     hosts, which is necessary to get energy consumption predictions.
 249     As usual, you should not trust our example, and you should strive
 250     to double-check that your instanciation matches your target platform.
 251     |br| `examples/platforms/energy_platform.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/platforms/energy_platform.xml>`_
 252
 253   - **Consumption due to the CPU:**
 254     This example shows how to retrieve the amount of energy consumed
 255     by the CPU during computations, and the impact of the pstate.
 256     |br| `examples/s4u/energy-exec/s4u-energy-exec.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/energy-exec/s4u-energy-exec.cpp>`_
 257
 258   - **Consumption due to the network:**
 259     This example shows how to retrieve and display the energy consumed
 260     by the network during communications.
 261     |br| `examples/s4u/energy-link/s4u-energy-link.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/energy-link/s4u-energy-link.cpp>`_
 262
 263   - **Modeling the shutdown and boot of hosts:**
 264     Simple example of model of model for the energy consumption during
 265     the host boot and shutdown periods.
 266     |br| `examples/s4u/energy-boot/platform_boot.xml <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/energy-boot/platform_boot.xml>`_
 267     |br| `examples/s4u/energy-boot/s4u-energy-boot.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/energy-boot/s4u-energy-boot.cpp>`_
 268
 269 .......................
 270 Tracing and Visualizing
 271 .......................
 272
 273 Tracing can be activated by various configuration options which
 274 are illustrated in these example. See also the
 275 :ref:`full list of options related to tracing <tracing_tracing_options>`.
 276
 277 It is interesting to run the process-create example with the following
 278 options to see the task executions:
 279
 280   - **Platform Tracing:**
 281     This program is a toy example just loading the platform, so that
 282     you can play with the platform visualization. Recommanded options:
 283     ``--cfg=tracing:yes --cfg=tracing/categorized:yes``
 284     |br| `examples/s4u/trace-platform/s4u-trace-platform.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/trace-platform/s4u-trace-platform.cpp>`_
 285
 286 ........................
 287 Larger SimGrid Examplars
 288 ........................
 289
 290 This section contains application examples that are somewhat larger
 291 than the previous examples.
 292
 293   - **Ping Pong:**
 294     This simple example just sends one message back and forth.
 295     The tesh file laying in the directory show how to start the simulator binary, highlighting how to pass options to
 296     the simulators (as detailed in Section :ref:`options`).
 297     |br| `examples/s4u/app-pingpong/s4u-app-pingpong.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/app-pingpong/s4u-app-pingpong.cpp>`_
 298
 299   - **Token ring:**
 300     Shows how to implement a classical communication pattern, where a
 301     token is exchanged along a ring to reach every participant.
 302     |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>`_
 303
 304   - **Master Workers:**
 305     Another good old example, where one Master process has a bunch of task to dispatch to a set of several Worker
 306     processes. This example comes in two equivalent variants, one
 307     where the actors are specified as simple functions (which is easier to
 308     understand for newcomers) and one where the actors are specified
 309     as classes (which is more powerful for the users wanting to build
 310     their own projects upon the example).
 311     |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>`_
 312     |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>`_
 313
 314 Data diffusion
 315 ^^^^^^^^^^^^^^
 316
 317   - **Bit Torrent:**
 318     Classical protocol for Peer-to-Peer data diffusion.
 319     |br| `examples/s4u/app-bittorrent/s4u-bittorrent.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/app-bittorrent/s4u-bittorrent.cpp>`_
 320
 321   - **Chained Send:**
 322     Data broadcast over a ring of processes.
 323     |br| `examples/s4u/app-chainsend/s4u-app-chainsend.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/app-chainsend/s4u-app-chainsend.cpp>`_
 324
 325 Distributed Hash Tables (DHT)
 326 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 327
 328   - **Chord Protocol**
 329     One of the most famous DHT protocol.
 330     |br| `examples/s4u/dht-chord/s4u-dht-chord.cpp <https://framagit.org/simgrid/simgrid/tree/master/examples/s4u/dht-chord/s4u-dht-chord.cpp>`_
 331
 332 .. TODO:: document here the examples about plugins
 333
 334 .. |br| raw:: html
 335
 336    <br />