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
365 I/O on Disks and Files
366 ----------------------
368 SimGrid provides two levels of abstraction to interact with the
369 simulated disks. At the simplest level, you simply create read and
370 write actions on the disk resources.
372 - **Access to raw disk devices:**
373 This example illustrates how to simply read and write data on a
374 simulated disk resource.
378 .. example-tab:: examples/s4u/io-disk-raw/s4u-io-disk-raw.cpp
380 .. example-tab:: examples/platforms/hosts_with_disks.xml
382 This shows how to declare disks in XML.
384 The FileSystem plugin provides a more detailed view, with the
385 classical operations over files: open, move, unlink, and of course
386 read and write. The file and disk sizes are also dealt with and can
387 result in short reads and short write, as in reality.
389 - **File Management:**
390 This example illustrates the use of operations on files
391 (read, write, seek, tell, unlink, etc).
395 .. example-tab:: examples/s4u/io-file-system/s4u-io-file-system.cpp
398 I/O operations on files can also be done in a remote fashion,
399 i.e. when the accessed disk is not mounted on the caller's host.
403 .. example-tab:: examples/s4u/io-file-remote/s4u-io-file-remote.cpp
407 Classical synchronization objects
408 ---------------------------------
411 Shows how to use simgrid::s4u::Mutex synchronization objects.
415 .. example-tab:: examples/s4u/synchro-mutex/s4u-synchro-mutex.cpp
418 Shows how to use simgrid::s4u::Barrier synchronization objects.
422 .. example-tab:: examples/s4u/synchro-barrier/s4u-synchro-barrier.cpp
425 Shows how to use simgrid::s4u::Semaphore synchronization objects.
429 .. example-tab:: examples/s4u/synchro-semaphore/s4u-synchro-semaphore.cpp
431 =============================
432 Interacting with the Platform
433 =============================
435 - **User-defined properties:**
436 You can attach arbitrary information to most platform elements from
437 the XML file, and then interact with these values from your
438 program. Note that the changes are not written permanently on disk,
439 in the XML file nor anywhere else. They only last until the end of
444 .. example-tab:: examples/s4u/platform-properties/s4u-platform-properties.cpp
446 - :cpp:func:`simgrid::s4u::Actor::get_property()` and :cpp:func:`simgrid::s4u::Actor::set_property()`
447 - :cpp:func:`simgrid::s4u::Host::get_property()` and :cpp:func:`simgrid::s4u::Host::set_property()`
448 - :cpp:func:`simgrid::s4u::Link::get_property()` and :cpp:func:`simgrid::s4u::Link::set_property()`
449 - :cpp:func:`simgrid::s4u::NetZone::get_property()` and :cpp:func:`simgrid::s4u::NetZone::set_property()`
455 .. showfile:: examples/s4u/platform-properties/s4u-platform-properties_d.xml
461 .. showfile:: examples/platforms/prop.xml
464 - **Retrieving the netzones matching a given criteria:**
465 Shows how to filter the cluster netzones.
469 .. example-tab:: examples/s4u/routing-get-clusters/s4u-routing-get-clusters.cpp
471 - **Retrieving the list of hosts matching a given criteria:**
472 Shows how to filter the actors that match a given criteria.
476 .. example-tab:: examples/s4u/engine-filtering/s4u-engine-filtering.cpp
478 - **Specifying state profiles:** shows how to specify when the
479 resources must be turned off and on again, and how to react to such
480 failures in your code. See also :ref:`howto_churn`.
484 .. example-tab:: examples/s4u/platform-failures/s4u-platform-failures.cpp
488 .. showfile:: examples/platforms/small_platform_failures.xml
491 .. showfile:: examples/platforms/profiles/jupiter_state.profile
493 .. showfile:: examples/platforms/profiles/bourassa_state.profile
495 .. showfile:: examples/platforms/profiles/fafard_state.profile
497 - **Specifying speed profiles:** shows how to specify an external
498 load to resources, variating their peak speed over time.
502 .. example-tab:: examples/s4u/platform-profile/s4u-platform-profile.cpp
506 .. showfile:: examples/platforms/small_platform_profile.xml
509 .. showfile:: examples/platforms/profiles/jupiter_speed.profile
511 .. showfile:: examples/platforms/profiles/link1_bandwidth.profile
513 .. showfile:: examples/platforms/profiles/link1_latency.profile
519 - **Describing the energy profiles in the platform:**
520 This platform file contains the energy profile of each links and
521 hosts, which is necessary to get energy consumption predictions.
522 As usual, you should not trust our example, and you should strive
523 to double-check that your instantiation matches your target platform.
527 .. example-tab:: examples/platforms/energy_platform.xml
529 - **Consumption due to the CPU:**
530 This example shows how to retrieve the amount of energy consumed
531 by the CPU during computations, and the impact of the pstate.
535 .. example-tab:: examples/s4u/energy-exec/s4u-energy-exec.cpp
537 - **Consumption due to the network:**
538 This example shows how to retrieve and display the energy consumed
539 by the network during communications.
543 .. example-tab:: examples/s4u/energy-link/s4u-energy-link.cpp
545 - **Modeling the shutdown and boot of hosts:**
546 Simple example of model of model for the energy consumption during
547 the host boot and shutdown periods.
551 .. example-tab:: examples/s4u/energy-boot/platform_boot.xml
553 .. example-tab:: examples/s4u/energy-boot/s4u-energy-boot.cpp
555 =======================
556 Tracing and Visualizing
557 =======================
559 Tracing can be activated by various configuration options which
560 are illustrated in these example. See also the
561 :ref:`full list of options related to tracing <tracing_tracing_options>`.
563 It is interesting to run the process-create example with the following
564 options to see the task executions:
566 - **Platform Tracing:**
567 This program is a toy example just loading the platform, so that
568 you can play with the platform visualization. Recommanded options:
569 ``--cfg=tracing:yes --cfg=tracing/categorized:yes``
573 .. example-tab:: examples/s4u/trace-platform/s4u-trace-platform.cpp
575 ========================
576 Larger SimGrid Examplars
577 ========================
579 This section contains application examples that are somewhat larger
580 than the previous examples.
583 This simple example just sends one message back and forth.
584 The tesh file laying in the directory show how to start the simulator binary, highlighting how to pass options to
585 the simulators (as detailed in Section :ref:`options`).
589 .. example-tab:: examples/s4u/app-pingpong/s4u-app-pingpong.cpp
592 Shows how to implement a classical communication pattern, where a
593 token is exchanged along a ring to reach every participant.
597 .. example-tab:: examples/s4u/app-token-ring/s4u-app-token-ring.cpp
599 - **Master Workers:**
600 Another good old example, where one Master process has a bunch of task to dispatch to a set of several Worker
607 This example comes in two equivalent variants, one where the actors
608 are specified as simple functions (which is easier to understand for
609 newcomers) and one where the actors are specified as classes (which is
610 more powerful for the users wanting to build their own projects upon
613 .. showfile:: examples/s4u/app-masterworkers/s4u-app-masterworkers-class.cpp
616 .. showfile:: examples/s4u/app-masterworkers/s4u-app-masterworkers-fun.cpp
623 Classical protocol for Peer-to-Peer data diffusion.
629 .. showfile:: examples/s4u/app-bittorrent/s4u-bittorrent.cpp
632 .. showfile:: examples/s4u/app-bittorrent/s4u-peer.cpp
635 .. showfile:: examples/s4u/app-bittorrent/s4u-tracker.cpp
639 Data broadcast over a ring of processes.
643 .. example-tab:: examples/s4u/app-chainsend/s4u-app-chainsend.cpp
645 Distributed Hash Tables (DHT)
646 -----------------------------
649 One of the most famous DHT protocol.
655 .. showfile:: examples/s4u/dht-chord/s4u-dht-chord.cpp
658 .. showfile:: examples/s4u/dht-chord/s4u-dht-chord-node.cpp
662 Another well-known DHT protocol.
668 .. showfile:: examples/s4u/dht-kademlia/s4u-dht-kademlia.cpp
671 .. showfile:: examples/s4u/dht-kademlia/routing_table.cpp
674 .. showfile:: examples/s4u/dht-kademlia/answer.cpp
677 .. showfile:: examples/s4u/dht-kademlia/node.cpp
686 This example starts some computations both on PMs and VMs, and
687 migrates some VMs around.
691 .. example-tab:: examples/s4u/cloud-simple/s4u-cloud-simple.cpp
694 This example shows how to migrate VMs between PMs.
698 .. example-tab:: examples/s4u/cloud-migration/s4u-cloud-migration.cpp
700 =======================
701 Model-Checking Examples
702 =======================
704 The model-checker can be used to exhaustively search for issues in the
705 tested application. It must be activated at compile time, but this
706 mode is rather experimental in SimGrid (as of v3.22). You should not
707 enable it unless you really want to formally verify your applications:
708 SimGrid is slower and maybe less robust when MC is enabled.
711 In this example, two actors send some data to a central server,
712 which asserts that the messages are always received in the same order.
713 This is obviously wrong, and the model-checker correctly finds a
714 counter-example to that assertion.
718 .. example-tab:: examples/s4u/mc-failing-assert/s4u-mc-failing-assert.cpp
724 .. |cpp| image:: /img/lang_cpp.png
728 .. |py| image:: /img/lang_python.png