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/c/actor-create/actor-create.c
59 You create actors either:
61 - Directly with :cpp:func:`sg_actor_create()` followed by :cpp:func:`sg_actor_start`.
62 - From XML with :cpp:func:`simgrid_register_function` and then :cpp:func:`simgrid_load_deployment`.
64 .. example-tab:: examples/python/actor-create/actor-create_d.xml
66 The following file is used in both C++ and Python.
68 - **React to the end of actors:** You can attach callbacks to the end of
69 actors. There is several ways of doing so, depending on whether you want to
70 attach your callback to a given actor and on how you define the end of a
71 given actor. User code probably want to react to the termination of an actor
72 while some plugins want to react to the destruction (memory collection) of
77 .. example-tab:: examples/s4u/actor-exiting/s4u-actor-exiting.cpp
79 This example shows how to attach a callback to:
81 - the end of a specific actor: :cpp:func:`simgrid::s4u::this_actor::on_exit()`
82 - the end of any actor: :cpp:member:`simgrid::s4u::Actor::on_termination()`
83 - the destruction of any actor: :cpp:member:`simgrid::s4u::Actor::on_destruction()`
85 .. example-tab:: examples/c/actor-exiting/actor-exiting.c
87 This example shows how to attach a callback to the end of a specific actor with
88 :cpp:func:`sg_actor_on_exit()`.
91 Actors can forcefully stop other actors.
95 .. example-tab:: examples/s4u/actor-kill/s4u-actor-kill.cpp
97 See also :cpp:func:`void simgrid::s4u::Actor::kill(void)`, :cpp:func:`void simgrid::s4u::Actor::kill_all()`,
98 :cpp:func:`simgrid::s4u::this_actor::exit`, :cpp:func:`simgrid::s4u::this_actor::on_exit`.
100 .. example-tab:: examples/python/actor-kill/actor-kill.py
102 See also :py:func:`simgrid.Actor.kill`, :py:func:`simgrid.Actor.kill_all`, :py:func:`simgrid.this_actor.exit`,
103 :py:func:`simgrid.this_actor.on_exit`.
105 .. example-tab:: examples/c/actor-kill/actor-kill.c
107 See also :cpp:func:`sg_actor_kill`, :cpp:func:`sg_actor_kill_all`, :cpp:func:`sg_actor_exit`, :cpp:func:`sg_actor_on_exit`.
109 - **Controling the actor life cycle from the XML:**
110 You can specify a start time and a kill time in the deployment file.
114 .. example-tab:: examples/s4u/actor-lifetime/s4u-actor-lifetime.cpp
116 This file is not really interesting: the important matter is in the XML file.
118 .. example-tab:: examples/s4u/actor-lifetime/s4u-actor-lifetime_d.xml
120 This demonstrates the ``start_time`` and ``kill_time`` attribute of the :ref:`pf_tag_actor` tag.
122 - **Daemonize actors:**
123 Some actors may be intended to simulate daemons that run in background. This example show how to transform a regular
124 actor into a daemon that will be automatically killed once the simulation is over.
128 .. example-tab:: examples/s4u/actor-daemon/s4u-actor-daemon.cpp
130 See also :cpp:func:`simgrid::s4u::Actor::daemonize()` and :cpp:func:`simgrid::s4u::Actor::is_daemon()`.
132 .. example-tab:: examples/python/actor-daemon/actor-daemon.py
134 See also :py:func:`simgrid.Actor.daemonize()` and :py:func:`simgrid.Actor.is_daemon()`.
136 .. example-tab:: examples/c/actor-daemon/actor-daemon.c
138 See also :cpp:func:`sg_actor_daemonize` and :cpp:func:`sg_actor_is_daemon`.
140 Inter-Actors Interactions
141 -------------------------
143 See also the examples on :ref:`inter-actors communications
144 <s4u_ex_communication>` and the ones on :ref:`classical
145 synchronization objects <s4u_ex_IPC>`.
147 - **Suspend and Resume actors:**
148 Actors can be suspended and resumed during their executions.
152 .. example-tab:: examples/s4u/actor-suspend/s4u-actor-suspend.cpp
154 See also :cpp:func:`simgrid::s4u::this_actor::suspend()`,
155 :cpp:func:`simgrid::s4u::Actor::suspend()`, :cpp:func:`simgrid::s4u::Actor::resume()`, and
156 :cpp:func:`simgrid::s4u::Actor::is_suspended()`.
158 .. example-tab:: examples/python/actor-suspend/actor-suspend.py
160 See also :py:func:`simgrid.this_actor.suspend()`,
161 :py:func:`simgrid.Actor.suspend()`, :py:func:`simgrid.Actor.resume()`, and
162 :py:func:`simgrid.Actor.is_suspended()`.
164 .. example-tab:: examples/c/actor-suspend/actor-suspend.c
166 See also :cpp:func:`sg_actor_suspend()`, :cpp:func:`sg_actor_resume()`, and
167 :cpp:func:`sg_actor_is_suspended()`.
169 - **Migrating Actors:**
170 Actors can move or be moved from a host to another very easily. It amount to setting them on a new host.
174 .. example-tab:: examples/s4u/actor-migrate/s4u-actor-migrate.cpp
176 See also :cpp:func:`simgrid::s4u::this_actor::set_host()` and :cpp:func:`simgrid::s4u::Actor::set_host()`.
178 .. example-tab:: examples/python/actor-migrate/actor-migrate.py
180 See also :py:func:`simgrid.this_actor.set_host()` and :py:func:`simgrid.Actor.set_host()`.
182 .. example-tab:: examples/c/actor-migrate/actor-migrate.c
184 See also :cpp:func:`sg_actor_set_host()`.
186 - **Waiting for the termination of an actor:** (joining on it)
187 You can block the current actor until the end of another actor.
191 .. example-tab:: examples/s4u/actor-join/s4u-actor-join.cpp
193 See also :cpp:func:`simgrid::s4u::Actor::join()`.
195 .. example-tab:: examples/python/actor-join/actor-join.py
197 See also :py:func:`simgrid.Actor.join()`.
199 .. example-tab:: examples/c/actor-join/actor-join.c
201 See also :cpp:func:`sg_actor_join`.
203 - **Yielding to other actors**.
204 The ```yield()``` function interrupts the execution of the current
205 actor, leaving a chance to the other actors that are ready to run
210 .. example-tab:: examples/s4u/actor-yield/s4u-actor-yield.cpp
212 See also :cpp:func:`simgrid::s4u::this_actor::yield()`.
214 .. example-tab:: examples/python/actor-yield/actor-yield.py
216 See also :py:func:`simgrid.this_actor.yield_()`.
218 .. example-tab:: examples/c/actor-yield/actor-yield.c
220 See also :cpp:func:`sg_actor_yield()`.
222 Traces Replay as a Workload
223 ---------------------------
225 This section details how to run trace-driven simulations. It is very
226 handy when you want to test an algorithm or protocol that only react
227 to external events. For example, many P2P protocols react to user
228 requests, but do nothing if there is no such event.
230 In such situations, you should write your protocol in C++, and separate
231 the workload that you want to play onto your protocol in a separate
232 text file. Declare a function handling each type of the events in your
233 trace, register them using :cpp:func:`xbt_replay_action_register()` in
234 your main, and then run the simulation.
236 Then, you can either have one trace file containing all your events,
237 or a file per simulated process: the former may be easier to work
238 with, but the second is more efficient on very large traces. Check
239 also the tesh files in the example directories for details.
241 - **Communication replay:**
242 Presents a set of event handlers reproducing classical communication
243 primitives (asynchronous send/receive at the moment).
247 .. example-tab:: examples/s4u/replay-comm/s4u-replay-comm.cpp
250 Presents a set of event handlers reproducing classical I/O
251 primitives (open, read, close).
255 .. example-tab:: examples/s4u/replay-io/s4u-replay-io.cpp
257 ==========================
258 Activities: what Actors do
259 ==========================
261 .. _s4u_ex_communication:
263 Communications on the Network
264 -----------------------------
266 - **Basic asynchronous communications:**
267 Illustrates how to have non-blocking communications, that are
268 communications running in the background leaving the process free
269 to do something else during their completion.
273 .. example-tab:: examples/s4u/async-wait/s4u-async-wait.cpp
275 See also :cpp:func:`simgrid::s4u::Mailbox::put_async()` and :cpp:func:`simgrid::s4u::Comm::wait()`.
277 .. example-tab:: examples/python/async-wait/async-wait.py
279 See also :py:func:`simgrid.Mailbox.put_async()` and :py:func:`simgrid.Comm.wait()`.
281 - **Waiting for all communications in a set:**
282 The ``wait_all()`` function is useful when you want to block until
283 all activities in a given set have completed.
287 .. example-tab:: examples/s4u/async-waitall/s4u-async-waitall.cpp
289 See also :cpp:func:`simgrid::s4u::Comm::wait_all()`.
291 .. example-tab:: examples/python/async-waitall/async-waitall.py
293 See also :py:func:`simgrid.Comm.wait_all()`.
295 - **Waiting for the first completed communication in a set:**
296 The ``wait_any()`` function is useful
297 when you want to block until one activity of the set completes, no
298 matter which terminates first.
302 .. example-tab:: examples/s4u/async-waitany/s4u-async-waitany.cpp
304 See also :cpp:func:`simgrid::s4u::Comm::wait_any()`.
306 .. example-tab:: examples/python/async-waitany/async-waitany.py
308 See also :py:func:`simgrid.Comm.wait_any()`.
310 .. example-tab:: examples/c/async-waitany/async-waitany.c
312 See also :cpp:func:`sg_comm_wait_any`.
314 .. _s4u_ex_execution:
316 Executions on the CPU
317 ---------------------
319 - **Basic execution:**
320 The computations done in your program are not reported to the
321 simulated world, unless you explicitly request the simulator to pause
322 the actor until a given amount of flops gets computed on its simulated
323 host. Some executions can be given an higher priority so that they
328 .. example-tab:: examples/s4u/exec-basic/s4u-exec-basic.cpp
330 See also :cpp:func:`void simgrid::s4u::this_actor::execute(double)`
331 and :cpp:func:`void simgrid::s4u::this_actor::execute(double, double)`.
333 .. example-tab:: examples/python/exec-basic/exec-basic.py
335 See also :py:func:`simgrid.this_actor.execute()`.
337 - **Asynchronous execution:**
338 You can start asynchronous executions, just like you would fire
343 .. example-tab:: examples/s4u/exec-async/s4u-exec-async.cpp
345 See also :cpp:func:`simgrid::s4u::this_actor::exec_init()`,
346 :cpp:func:`simgrid::s4u::Activity::start()`,
347 :cpp:func:`simgrid::s4u::Activity::wait()`,
348 :cpp:func:`simgrid::s4u::Activity::get_remaining()`,
349 :cpp:func:`simgrid::s4u::Exec::get_remaining_ratio()`,
350 :cpp:func:`simgrid::s4u::this_actor::exec_async()` and
351 :cpp:func:`simgrid::s4u::Activity::cancel()`.
353 .. example-tab:: examples/python/exec-async/exec-async.py
355 See also :py:func:`simgrid.this_actor::exec_init()`,
356 :py:func:`simgrid.Activity::start()`,
357 :py:func:`simgrid.Activity.wait()`,
358 :py:func:`simgrid.Activity.get_remaining()`,
359 :py:func:`simgrid.Exec.get_remaining_ratio()`,
360 :py:func:`simgrid.this_actor.exec_async()` and
361 :py:func:`simgrid.Activity.cancel()`.
363 - **Remote execution:**
364 You can start executions on remote hosts, or even change the host
365 on which they occur during their execution.
369 .. example-tab:: examples/s4u/exec-remote/s4u-exec-remote.cpp
371 See also :cpp:func:`simgrid::s4u::Exec::set_host()`.
373 .. example-tab:: examples/python/exec-remote/exec-remote.py
375 See also :py:func:`simgrid.Exec.set_host()`.
377 - **Parallel executions:**
378 These objects are convenient abstractions of parallel
379 computational kernels that span over several machines, such as a
380 PDGEM and the other ScaLAPACK routines. Note that this only works
381 with the "ptask_L07" host model (``--cfg=host/model:ptask_L07``).
385 .. example-tab:: examples/s4u/exec-ptask/s4u-exec-ptask.cpp
387 See also :cpp:func:`simgrid::s4u::this_actor::parallel_execute()`.
389 - **Using Pstates on a host:**
390 This example shows how define a set of pstates in the XML. The current pstate
391 of an host can then be accessed and changed from the program.
395 .. example-tab:: examples/s4u/exec-dvfs/s4u-exec-dvfs.cpp
397 See also :cpp:func:`simgrid::s4u::Host::get_pstate_speed` and :cpp:func:`simgrid::s4u::Host::set_pstate`.
399 .. example-tab:: examples/python/exec-dvfs/exec-dvfs.py
401 See also :py:func:`Host.get_pstate_speed` and :py:func:`Host.set_pstate`.
403 .. example-tab:: examples/platforms/energy_platform.xml
407 I/O on Disks and Files
408 ----------------------
410 SimGrid provides two levels of abstraction to interact with the
411 simulated disks. At the simplest level, you simply create read and
412 write actions on the disk resources.
414 - **Access to raw disk devices:**
415 This example illustrates how to simply read and write data on a
416 simulated disk resource.
420 .. example-tab:: examples/s4u/io-disk-raw/s4u-io-disk-raw.cpp
422 .. example-tab:: examples/platforms/hosts_with_disks.xml
424 This shows how to declare disks in XML.
426 The FileSystem plugin provides a more detailed view, with the
427 classical operations over files: open, move, unlink, and of course
428 read and write. The file and disk sizes are also dealt with and can
429 result in short reads and short write, as in reality.
431 - **File Management:**
432 This example illustrates the use of operations on files
433 (read, write, seek, tell, unlink, etc).
437 .. example-tab:: examples/s4u/io-file-system/s4u-io-file-system.cpp
440 I/O operations on files can also be done in a remote fashion,
441 i.e. when the accessed disk is not mounted on the caller's host.
445 .. example-tab:: examples/s4u/io-file-remote/s4u-io-file-remote.cpp
449 Classical synchronization objects
450 ---------------------------------
453 Shows how to use :cpp:type:`simgrid::s4u::Barrier` synchronization objects.
457 .. example-tab:: examples/s4u/synchro-barrier/s4u-synchro-barrier.cpp
459 - **Condition variable:**
460 Shows how to use :cpp:type:`simgrid::s4u::ConditionVariable` synchronization objects.
464 .. example-tab:: examples/s4u/synchro-condition-variable/s4u-synchro-condition-variable.cpp
467 Shows how to use :cpp:type:`simgrid::s4u::Mutex` synchronization objects.
471 .. example-tab:: examples/s4u/synchro-mutex/s4u-synchro-mutex.cpp
474 Shows how to use :cpp:type:`simgrid::s4u::Semaphore` synchronization objects.
478 .. example-tab:: examples/s4u/synchro-semaphore/s4u-synchro-semaphore.cpp
480 =============================
481 Interacting with the Platform
482 =============================
484 - **User-defined properties:**
485 You can attach arbitrary information to most platform elements from
486 the XML file, and then interact with these values from your
487 program. Note that the changes are not written permanently on disk,
488 in the XML file nor anywhere else. They only last until the end of
493 .. example-tab:: examples/s4u/platform-properties/s4u-platform-properties.cpp
495 - :cpp:func:`simgrid::s4u::Actor::get_property()` and :cpp:func:`simgrid::s4u::Actor::set_property()`
496 - :cpp:func:`simgrid::s4u::Host::get_property()` and :cpp:func:`simgrid::s4u::Host::set_property()`
497 - :cpp:func:`simgrid::s4u::Link::get_property()` and :cpp:func:`simgrid::s4u::Link::set_property()`
498 - :cpp:func:`simgrid::s4u::NetZone::get_property()` and :cpp:func:`simgrid::s4u::NetZone::set_property()`
504 .. showfile:: examples/s4u/platform-properties/s4u-platform-properties_d.xml
510 .. showfile:: examples/platforms/prop.xml
513 - **Retrieving the netzones matching a given criteria:**
514 Shows how to filter the cluster netzones.
518 .. example-tab:: examples/s4u/routing-get-clusters/s4u-routing-get-clusters.cpp
520 - **Retrieving the list of hosts matching a given criteria:**
521 Shows how to filter the actors that match a given criteria.
525 .. example-tab:: examples/s4u/engine-filtering/s4u-engine-filtering.cpp
527 - **Specifying state profiles:** shows how to specify when the
528 resources must be turned off and on again, and how to react to such
529 failures in your code. See also :ref:`howto_churn`.
533 .. example-tab:: examples/s4u/platform-failures/s4u-platform-failures.cpp
537 .. showfile:: examples/platforms/small_platform_failures.xml
540 .. showfile:: examples/platforms/profiles/jupiter_state.profile
542 .. showfile:: examples/platforms/profiles/bourassa_state.profile
544 .. showfile:: examples/platforms/profiles/fafard_state.profile
546 - **Specifying speed profiles:** shows how to specify an external
547 load to resources, variating their peak speed over time.
551 .. example-tab:: examples/s4u/platform-profile/s4u-platform-profile.cpp
555 .. showfile:: examples/platforms/small_platform_profile.xml
558 .. showfile:: examples/platforms/profiles/jupiter_speed.profile
560 .. showfile:: examples/platforms/profiles/link1_bandwidth.profile
562 .. showfile:: examples/platforms/profiles/link1_latency.profile
568 - **Describing the energy profiles in the platform:**
569 This platform file contains the energy profile of each links and
570 hosts, which is necessary to get energy consumption predictions.
571 As usual, you should not trust our example, and you should strive
572 to double-check that your instantiation matches your target platform.
576 .. example-tab:: examples/platforms/energy_platform.xml
578 - **Consumption due to the CPU:**
579 This example shows how to retrieve the amount of energy consumed
580 by the CPU during computations, and the impact of the pstate.
584 .. example-tab:: examples/s4u/energy-exec/s4u-energy-exec.cpp
586 - **Consumption due to the network:**
587 This example shows how to retrieve and display the energy consumed
588 by the network during communications.
592 .. example-tab:: examples/s4u/energy-link/s4u-energy-link.cpp
594 - **Modeling the shutdown and boot of hosts:**
595 Simple example of model of model for the energy consumption during
596 the host boot and shutdown periods.
600 .. example-tab:: examples/s4u/energy-boot/platform_boot.xml
602 .. example-tab:: examples/s4u/energy-boot/s4u-energy-boot.cpp
604 =======================
605 Tracing and Visualizing
606 =======================
608 Tracing can be activated by various configuration options which
609 are illustrated in these example. See also the
610 :ref:`full list of options related to tracing <tracing_tracing_options>`.
612 It is interesting to run the process-create example with the following
613 options to see the task executions:
615 - **Platform Tracing:**
616 This program is a toy example just loading the platform, so that
617 you can play with the platform visualization. Recommanded options:
618 ``--cfg=tracing:yes --cfg=tracing/categorized:yes``
622 .. example-tab:: examples/s4u/trace-platform/s4u-trace-platform.cpp
624 ========================
625 Larger SimGrid Examplars
626 ========================
628 This section contains application examples that are somewhat larger
629 than the previous examples.
632 This simple example just sends one message back and forth.
633 The tesh file laying in the directory show how to start the simulator binary, highlighting how to pass options to
634 the simulators (as detailed in Section :ref:`options`).
638 .. example-tab:: examples/s4u/app-pingpong/s4u-app-pingpong.cpp
641 Shows how to implement a classical communication pattern, where a
642 token is exchanged along a ring to reach every participant.
646 .. example-tab:: examples/s4u/app-token-ring/s4u-app-token-ring.cpp
648 - **Master Workers:**
649 Another good old example, where one Master process has a bunch of task to dispatch to a set of several Worker
656 This example comes in two equivalent variants, one where the actors
657 are specified as simple functions (which is easier to understand for
658 newcomers) and one where the actors are specified as classes (which is
659 more powerful for the users wanting to build their own projects upon
662 .. showfile:: examples/s4u/app-masterworkers/s4u-app-masterworkers-class.cpp
665 .. showfile:: examples/s4u/app-masterworkers/s4u-app-masterworkers-fun.cpp
672 Classical protocol for Peer-to-Peer data diffusion.
678 .. showfile:: examples/s4u/app-bittorrent/s4u-bittorrent.cpp
681 .. showfile:: examples/s4u/app-bittorrent/s4u-peer.cpp
684 .. showfile:: examples/s4u/app-bittorrent/s4u-tracker.cpp
688 Data broadcast over a ring of processes.
692 .. example-tab:: examples/s4u/app-chainsend/s4u-app-chainsend.cpp
694 Distributed Hash Tables (DHT)
695 -----------------------------
698 One of the most famous DHT protocol.
704 .. showfile:: examples/s4u/dht-chord/s4u-dht-chord.cpp
707 .. showfile:: examples/s4u/dht-chord/s4u-dht-chord-node.cpp
711 Another well-known DHT protocol.
717 .. showfile:: examples/s4u/dht-kademlia/s4u-dht-kademlia.cpp
720 .. showfile:: examples/s4u/dht-kademlia/routing_table.cpp
723 .. showfile:: examples/s4u/dht-kademlia/answer.cpp
726 .. showfile:: examples/s4u/dht-kademlia/node.cpp
735 This example starts some computations both on PMs and VMs, and
736 migrates some VMs around.
740 .. example-tab:: examples/s4u/cloud-simple/s4u-cloud-simple.cpp
743 This example shows how to migrate VMs between PMs.
747 .. example-tab:: examples/s4u/cloud-migration/s4u-cloud-migration.cpp
749 =======================
750 Model-Checking Examples
751 =======================
753 The model-checker can be used to exhaustively search for issues in the
754 tested application. It must be activated at compile time, but this
755 mode is rather experimental in SimGrid (as of v3.22). You should not
756 enable it unless you really want to formally verify your applications:
757 SimGrid is slower and maybe less robust when MC is enabled.
760 In this example, two actors send some data to a central server,
761 which asserts that the messages are always received in the same order.
762 This is obviously wrong, and the model-checker correctly finds a
763 counter-example to that assertion.
767 .. example-tab:: examples/s4u/mc-failing-assert/s4u-mc-failing-assert.cpp
773 .. |cpp| image:: /img/lang_cpp.png
777 .. |py| image:: /img/lang_python.png