1 .. S4U (Simgrid for you) is the modern interface of SimGrid, which new project should use.
3 .. This file follows the ReStructured syntax to be included in the
4 .. documentation, but it should remain readable directly.
10 SimGrid comes with an extensive set of examples, documented on this
11 page. Most of them only demonstrate one single feature, with some
12 larger examplars listed below.
14 The C++ examples can be found under examples/s4u while python examples
15 are in examples/python. Each such directory contains the source code (also listed
16 from this page), and the so-called tesh file containing how to call
17 the binary obtained by compiling this example and also the expected
18 output. Tesh files are used to turn each of our examples into an
19 integration test. Some examples also contain other files, on need.
21 A good way to bootstrap your own project is to copy and combine some
22 of the provided examples to constitute the skeleton of what you plan
27 ===========================
28 Actors: the Active Entities
29 ===========================
31 Starting and Stoping Actors
32 ---------------------------
34 - **Creating actors:**
35 Most actors are started from the deployment XML file, because this
36 is a :ref:`better scientific habbit <howto_science>`, but you can
37 also create them directly from your code.
41 .. example-tab:: examples/s4u/actor-create/s4u-actor-create.cpp
43 You create actors either:
45 - Directly with :cpp:func:`simgrid::s4u::Actor::create`
46 - From XML with :cpp:func:`simgrid::s4u::Engine::register_actor` (if your actor is a class)
47 or :cpp:func:`simgrid::s4u::Engine::register_function` (if your actor is a function)
48 and then :cpp:func:`simgrid::s4u::Engine::load_deployment`
50 .. example-tab:: examples/python/actor-create/actor-create.py
52 You create actors either:
54 - Directly with :py:func:`simgrid.Actor.create()`
55 - From XML with :py:func:`simgrid.Engine.register_actor()` and then :py:func:`simgrid.Engine.load_deployment()`
57 .. example-tab:: examples/python/actor-create/actor-create_d.xml
59 The following file is used in both C++ and Python.
61 - **React to the end of actors:** You can attach callbacks to the end of
62 actors. There is several ways of doing so, depending on whether you want to
63 attach your callback to a given actor and on how you define the end of a
64 given actor. User code probably want to react to the termination of an actor
65 while some plugins want to react to the destruction (memory collection) of
70 .. example-tab:: examples/s4u/actor-exiting/s4u-actor-exiting.cpp
72 This example shows how to attach a callback to:
74 - the end of a specific actor: :cpp:func:`simgrid::s4u::this_actor::on_exit()`
75 - the end of any actor: :cpp:member:`simgrid::s4u::Actor::on_termination()`
76 - the destruction of any actor: :cpp:member:`simgrid::s4u::Actor::on_destruction()`
79 Actors can forcefully stop other actors.
83 .. example-tab:: examples/s4u/actor-kill/s4u-actor-kill.cpp
85 See also :cpp:func:`void simgrid::s4u::Actor::kill(void)`, :cpp:func:`void simgrid::s4u::Actor::kill_all()`,
86 :cpp:func:`simgrid::s4u::this_actor::exit`.
88 .. example-tab:: examples/python/actor-kill/actor-kill.py
90 See also :py:func:`simgrid.Actor.kill`, :py:func:`simgrid.Actor.kill_all`, :py:func:`simgrid.this_actor.exit`.
92 - **Controling the actor life cycle from the XML:**
93 You can specify a start time and a kill time in the deployment file.
97 .. example-tab:: examples/s4u/actor-lifetime/s4u-actor-lifetime.cpp
99 This file is not really interesting: the important matter is in the XML file.
101 .. example-tab:: examples/s4u/actor-lifetime/s4u-actor-lifetime_d.xml
103 This demonstrates the ``start_time`` and ``kill_time`` attribute of the :ref:`pf_tag_actor` tag.
105 - **Daemonize actors:**
106 Some actors may be intended to simulate daemons that run in background. This example show how to transform a regular
107 actor into a daemon that will be automatically killed once the simulation is over.
111 .. example-tab:: examples/s4u/actor-daemon/s4u-actor-daemon.cpp
113 See also :cpp:func:`simgrid::s4u::Actor::daemonize()` and :cpp:func:`simgrid::s4u::Actor::is_daemon()`.
115 .. example-tab:: examples/python/actor-daemon/actor-daemon.py
117 See also :py:func:`simgrid.Actor.daemonize()` and :py:func:`simgrid.Actor.is_daemon()`.
119 Inter-Actors Interactions
120 -------------------------
122 See also the examples on :ref:`inter-actors communications
123 <s4u_ex_communication>` and the ones on :ref:`classical
124 synchronization objects <s4u_ex_IPC>`.
126 - **Suspend and Resume actors:**
127 Actors can be suspended and resumed during their executions.
131 .. example-tab:: examples/s4u/actor-suspend/s4u-actor-suspend.cpp
133 See also :cpp:func:`simgrid::s4u::this_actor::suspend()`,
134 :cpp:func:`simgrid::s4u::Actor::suspend()`, :cpp:func:`simgrid::s4u::Actor::resume()` and
135 :cpp:func:`simgrid::s4u::Actor::is_suspended()`.
137 .. example-tab:: examples/python/actor-suspend/actor-suspend.py
139 See also :py:func:`simgrid.this_actor.suspend()`,
140 :py:func:`simgrid.Actor.suspend()`, :py:func:`simgrid.Actor.resume()` and
141 :py:func:`simgrid.Actor.is_suspended()`.
143 - **Migrating Actors:**
144 Actors can move or be moved from a host to another very easily.
148 .. example-tab:: examples/s4u/actor-migrate/s4u-actor-migrate.cpp
150 See also :cpp:func:`simgrid::s4u::this_actor::migrate()` and :cpp:func:`simgrid::s4u::Actor::migrate()`.
152 .. example-tab:: examples/python/actor-migrate/actor-migrate.py
154 See also :py:func:`simgrid.this_actor.migrate()` and :py:func:`simgrid.Actor.migrate()`.
156 - **Waiting for the termination of an actor:** (joining on it)
157 You can block the current actor until the end of another actor.
161 .. example-tab:: examples/s4u/actor-join/s4u-actor-join.cpp
163 See also :cpp:func:`simgrid::s4u::Actor::join()`.
165 .. example-tab:: examples/python/actor-join/actor-join.py
167 See also :py:func:`simgrid.Actor.join()`.
169 - **Yielding to other actors**.
170 The ```yield()``` function interrupts the execution of the current
171 actor, leaving a chance to the other actors that are ready to run
176 .. example-tab:: examples/s4u/actor-yield/s4u-actor-yield.cpp
178 See also :cpp:func:`simgrid::s4u::this_actor::yield()`.
180 .. example-tab:: examples/python/actor-yield/actor-yield.py
182 See also :py:func:`simgrid.this_actor.yield_()`.
184 Traces Replay as a Workload
185 ---------------------------
187 This section details how to run trace-driven simulations. It is very
188 handy when you want to test an algorithm or protocol that only react
189 to external events. For example, many P2P protocols react to user
190 requests, but do nothing if there is no such event.
192 In such situations, you should write your protocol in C++, and separate
193 the workload that you want to play onto your protocol in a separate
194 text file. Declare a function handling each type of the events in your
195 trace, register them using :cpp:func:`xbt_replay_action_register()` in
196 your main, and then run the simulation.
198 Then, you can either have one trace file containing all your events,
199 or a file per simulated process: the former may be easier to work
200 with, but the second is more efficient on very large traces. Check
201 also the tesh files in the example directories for details.
203 - **Communication replay:**
204 Presents a set of event handlers reproducing classical communication
205 primitives (asynchronous send/receive at the moment).
209 .. example-tab:: examples/s4u/replay-comm/s4u-replay-comm.cpp
212 Presents a set of event handlers reproducing classical I/O
213 primitives (open, read, close).
217 .. example-tab:: examples/s4u/replay-io/s4u-replay-io.cpp
219 ==========================
220 Activities: what Actors do
221 ==========================
223 .. _s4u_ex_communication:
225 Communications on the Network
226 -----------------------------
228 - **Basic asynchronous communications:**
229 Illustrates how to have non-blocking communications, that are
230 communications running in the background leaving the process free
231 to do something else during their completion.
235 .. example-tab:: examples/s4u/async-wait/s4u-async-wait.cpp
237 See also :cpp:func:`simgrid::s4u::Mailbox::put_async()` and :cpp:func:`simgrid::s4u::Comm::wait()`.
239 .. example-tab:: examples/python/async-wait/async-wait.py
241 See also :py:func:`simgrid.Mailbox.put_async()` and :py:func:`simgrid.Comm.wait()`.
243 - **Waiting for all communications in a set:**
244 The ``wait_all()`` function is useful when you want to block until
245 all activities in a given set have completed.
249 .. example-tab:: examples/s4u/async-waitall/s4u-async-waitall.cpp
251 See also :cpp:func:`simgrid::s4u::Comm::wait_all()`.
253 .. example-tab:: examples/python/async-waitall/async-waitall.py
255 See also :py:func:`simgrid.Comm.wait_all()`.
257 - **Waiting for the first completed communication in a set:**
258 The ``wait_any()`` function is useful
259 when you want to block until one activity of the set completes, no
260 matter which terminates first.
264 .. example-tab:: examples/s4u/async-waitany/s4u-async-waitany.cpp
266 See also :cpp:func:`simgrid::s4u::Comm::wait_any()`.
268 .. example-tab:: examples/python/async-waitany/async-waitany.py
270 See also :py:func:`simgrid.Comm.wait_any()`.
272 .. _s4u_ex_execution:
274 Executions on the CPU
275 ---------------------
277 - **Basic execution:**
278 The computations done in your program are not reported to the
279 simulated world, unless you explicitly request the simulator to pause
280 the actor until a given amount of flops gets computed on its simulated
281 host. Some executions can be given an higher priority so that they
286 .. example-tab:: examples/s4u/exec-basic/s4u-exec-basic.cpp
288 See also :cpp:func:`void simgrid::s4u::this_actor::execute(double)`
289 and :cpp:func:`void simgrid::s4u::this_actor::execute(double, double)`.
291 .. example-tab:: examples/python/exec-basic/exec-basic.py
293 See also :py:func:`simgrid.this_actor.execute()`.
295 - **Asynchronous execution:**
296 You can start asynchronous executions, just like you would fire
301 .. example-tab:: examples/s4u/exec-async/s4u-exec-async.cpp
303 See also :cpp:func:`simgrid::s4u::this_actor::exec_init()`,
304 :cpp:func:`simgrid::s4u::Activity::start()`,
305 :cpp:func:`simgrid::s4u::Activity::wait()`,
306 :cpp:func:`simgrid::s4u::Activity::get_remaining()`,
307 :cpp:func:`simgrid::s4u::Exec::get_remaining_ratio()`,
308 :cpp:func:`simgrid::s4u::this_actor::exec_async()` and
309 :cpp:func:`simgrid::s4u::Activity::cancel()`.
311 .. example-tab:: examples/python/exec-async/exec-async.py
313 See also :py:func:`simgrid.this_actor::exec_init()`,
314 :py:func:`simgrid.Activity::start()`,
315 :py:func:`simgrid.Activity.wait()`,
316 :py:func:`simgrid.Activity.get_remaining()`,
317 :py:func:`simgrid.Exec.get_remaining_ratio()`,
318 :py:func:`simgrid.this_actor.exec_async()` and
319 :py:func:`simgrid.Activity.cancel()`.
321 - **Remote execution:**
322 You can start executions on remote hosts, or even change the host
323 on which they occur during their execution.
327 .. example-tab:: examples/s4u/exec-remote/s4u-exec-remote.cpp
329 See also :cpp:func:`simgrid::s4u::Exec::set_host()`.
331 .. example-tab:: examples/python/exec-remote/exec-remote.py
333 See also :py:func:`simgrid.Exec.set_host()`.
335 - **Parallel executions:**
336 These objects are convenient abstractions of parallel
337 computational kernels that span over several machines, such as a
338 PDGEM and the other ScaLAPACK routines. Note that this only works
339 with the "ptask_L07" host model (``--cfg=host/model:ptask_L07``).
343 .. example-tab:: examples/s4u/exec-ptask/s4u-exec-ptask.cpp
345 See also :cpp:func:`simgrid::s4u::this_actor::parallel_execute()`.
347 - **Using Pstates on a host:**
348 This example shows how define a set of pstates in the XML. The current pstate
349 of an host can then be accessed and changed from the program.
353 .. example-tab:: examples/s4u/exec-dvfs/s4u-exec-dvfs.cpp
355 See also :cpp:func:`simgrid::s4u::Host::get_pstate_speed` and :cpp:func:`simgrid::s4u::Host::set_pstate`.
357 .. example-tab:: examples/python/exec-dvfs/exec-dvfs.py
359 See also :py:func:`Host.get_pstate_speed` and :py:func:`Host.set_pstate`.
361 .. example-tab:: examples/platforms/energy_platform.xml
363 I/O on Disks and Files
364 ----------------------
366 SimGrid provides two levels of abstraction to interact with the
367 simulated disks. At the simplest level, you simply create read and
368 write actions on the disk resources.
370 - **Access to raw disk devices:**
371 This example illustrates how to simply read and write data on a
372 simulated disk resource.
376 .. example-tab:: examples/s4u/io-disk-raw/s4u-io-disk-raw.cpp
378 .. example-tab:: examples/platforms/hosts_with_disks.xml
380 This shows how to declare disks in XML.
382 The FileSystem plugin provides a more detailed view, with the
383 classical operations over files: open, move, unlink, and of course
384 read and write. The file and disk sizes are also dealt with and can
385 result in short reads and short write, as in reality.
387 - **File Management:**
388 This example illustrates the use of operations on files
389 (read, write, seek, tell, unlink, etc).
393 .. example-tab:: examples/s4u/io-file-system/s4u-io-file-system.cpp
396 I/O operations on files can also be done in a remote fashion,
397 i.e. when the accessed disk is not mounted on the caller's host.
401 .. example-tab:: examples/s4u/io-file-remote/s4u-io-file-remote.cpp
405 Classical synchronization objects
406 ---------------------------------
409 Shows how to use simgrid::s4u::Mutex synchronization objects.
413 .. example-tab:: examples/s4u/synchro-mutex/s4u-synchro-mutex.cpp
416 Shows how to use simgrid::s4u::Barrier synchronization objects.
420 .. example-tab:: examples/s4u/synchro-barrier/s4u-synchro-barrier.cpp
423 Shows how to use simgrid::s4u::Semaphore synchronization objects.
427 .. example-tab:: examples/s4u/synchro-semaphore/s4u-synchro-semaphore.cpp
429 =============================
430 Interacting with the Platform
431 =============================
433 - **User-defined properties:**
434 You can attach arbitrary information to most platform elements from
435 the XML file, and then interact with these values from your
436 program. Note that the changes are not written permanently on disk,
437 in the XML file nor anywhere else. They only last until the end of
442 .. example-tab:: examples/s4u/platform-properties/s4u-platform-properties.cpp
444 - :cpp:func:`simgrid::s4u::Actor::get_property()` and :cpp:func:`simgrid::s4u::Actor::set_property()`
445 - :cpp:func:`simgrid::s4u::Host::get_property()` and :cpp:func:`simgrid::s4u::Host::set_property()`
446 - :cpp:func:`simgrid::s4u::Link::get_property()` and :cpp:func:`simgrid::s4u::Link::set_property()`
447 - :cpp:func:`simgrid::s4u::NetZone::get_property()` and :cpp:func:`simgrid::s4u::NetZone::set_property()`
453 .. showfile:: examples/s4u/platform-properties/s4u-platform-properties_d.xml
459 .. showfile:: examples/platforms/prop.xml
462 - **Retrieving the netzones matching a given criteria:**
463 Shows how to filter the cluster netzones.
467 .. example-tab:: examples/s4u/routing-get-clusters/s4u-routing-get-clusters.cpp
469 - **Retrieving the list of hosts matching a given criteria:**
470 Shows how to filter the actors that match a given criteria.
474 .. example-tab:: examples/s4u/engine-filtering/s4u-engine-filtering.cpp
476 - **Specifying state profiles:** shows how to specify when the
477 resources must be turned off and on again, and how to react to such
478 failures in your code. See also :ref:`howto_churn`.
482 .. example-tab:: examples/s4u/platform-failures/s4u-platform-failures.cpp
486 .. showfile:: examples/platforms/small_platform_failures.xml
489 .. showfile:: examples/platforms/profiles/jupiter_state.profile
491 .. showfile:: examples/platforms/profiles/bourassa_state.profile
493 .. showfile:: examples/platforms/profiles/fafard_state.profile
495 - **Specifying speed profiles:** shows how to specify an external
496 load to resources, variating their peak speed over time.
500 .. example-tab:: examples/s4u/platform-profile/s4u-platform-profile.cpp
504 .. showfile:: examples/platforms/small_platform_profile.xml
507 .. showfile:: examples/platforms/profiles/jupiter_speed.profile
509 .. showfile:: examples/platforms/profiles/link1_bandwidth.profile
511 .. showfile:: examples/platforms/profiles/link1_latency.profile
517 - **Describing the energy profiles in the platform:**
518 This platform file contains the energy profile of each links and
519 hosts, which is necessary to get energy consumption predictions.
520 As usual, you should not trust our example, and you should strive
521 to double-check that your instantiation matches your target platform.
525 .. example-tab:: examples/platforms/energy_platform.xml
527 - **Consumption due to the CPU:**
528 This example shows how to retrieve the amount of energy consumed
529 by the CPU during computations, and the impact of the pstate.
533 .. example-tab:: examples/s4u/energy-exec/s4u-energy-exec.cpp
535 - **Consumption due to the network:**
536 This example shows how to retrieve and display the energy consumed
537 by the network during communications.
541 .. example-tab:: examples/s4u/energy-link/s4u-energy-link.cpp
543 - **Modeling the shutdown and boot of hosts:**
544 Simple example of model of model for the energy consumption during
545 the host boot and shutdown periods.
549 .. example-tab:: examples/s4u/energy-boot/platform_boot.xml
551 .. example-tab:: examples/s4u/energy-boot/s4u-energy-boot.cpp
553 =======================
554 Tracing and Visualizing
555 =======================
557 Tracing can be activated by various configuration options which
558 are illustrated in these example. See also the
559 :ref:`full list of options related to tracing <tracing_tracing_options>`.
561 It is interesting to run the process-create example with the following
562 options to see the task executions:
564 - **Platform Tracing:**
565 This program is a toy example just loading the platform, so that
566 you can play with the platform visualization. Recommanded options:
567 ``--cfg=tracing:yes --cfg=tracing/categorized:yes``
571 .. example-tab:: examples/s4u/trace-platform/s4u-trace-platform.cpp
573 ========================
574 Larger SimGrid Examplars
575 ========================
577 This section contains application examples that are somewhat larger
578 than the previous examples.
581 This simple example just sends one message back and forth.
582 The tesh file laying in the directory show how to start the simulator binary, highlighting how to pass options to
583 the simulators (as detailed in Section :ref:`options`).
587 .. example-tab:: examples/s4u/app-pingpong/s4u-app-pingpong.cpp
590 Shows how to implement a classical communication pattern, where a
591 token is exchanged along a ring to reach every participant.
595 .. example-tab:: examples/s4u/app-token-ring/s4u-app-token-ring.cpp
597 - **Master Workers:**
598 Another good old example, where one Master process has a bunch of task to dispatch to a set of several Worker
605 This example comes in two equivalent variants, one where the actors
606 are specified as simple functions (which is easier to understand for
607 newcomers) and one where the actors are specified as classes (which is
608 more powerful for the users wanting to build their own projects upon
611 .. showfile:: examples/s4u/app-masterworkers/s4u-app-masterworkers-class.cpp
614 .. showfile:: examples/s4u/app-masterworkers/s4u-app-masterworkers-fun.cpp
621 Classical protocol for Peer-to-Peer data diffusion.
627 .. showfile:: examples/s4u/app-bittorrent/s4u-bittorrent.cpp
630 .. showfile:: examples/s4u/app-bittorrent/s4u-peer.cpp
633 .. showfile:: examples/s4u/app-bittorrent/s4u-tracker.cpp
637 Data broadcast over a ring of processes.
641 .. example-tab:: examples/s4u/app-chainsend/s4u-app-chainsend.cpp
643 Distributed Hash Tables (DHT)
644 -----------------------------
647 One of the most famous DHT protocol.
653 .. showfile:: examples/s4u/dht-chord/s4u-dht-chord.cpp
656 .. showfile:: examples/s4u/dht-chord/s4u-dht-chord-node.cpp
660 Another well-known DHT protocol.
666 .. showfile:: examples/s4u/dht-kademlia/s4u-dht-kademlia.cpp
669 .. showfile:: examples/s4u/dht-kademlia/routing_table.cpp
672 .. showfile:: examples/s4u/dht-kademlia/answer.cpp
675 .. showfile:: examples/s4u/dht-kademlia/node.cpp
684 This example starts some computations both on PMs and VMs, and
685 migrates some VMs around.
689 .. example-tab:: examples/s4u/cloud-simple/s4u-cloud-simple.cpp
692 This example shows how to migrate VMs between PMs.
696 .. example-tab:: examples/s4u/cloud-migration/s4u-cloud-migration.cpp
698 =======================
699 Model-Checking Examples
700 =======================
702 The model-checker can be used to exhaustively search for issues in the
703 tested application. It must be activated at compile time, but this
704 mode is rather experimental in SimGrid (as of v3.22). You should not
705 enable it unless you really want to formally verify your applications:
706 SimGrid is slower and maybe less robust when MC is enabled.
709 In this example, two actors send some data to a central server,
710 which asserts that the messages are always received in the same order.
711 This is obviously wrong, and the model-checker correctly finds a
712 counter-example to that assertion.
716 .. example-tab:: examples/s4u/mc-failing-assert/s4u-mc-failing-assert.cpp
722 .. |cpp| image:: /img/lang_cpp.png
726 .. |py| image:: /img/lang_python.png