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()`
86 Actors can forcefully stop other actors.
90 .. example-tab:: examples/s4u/actor-kill/s4u-actor-kill.cpp
92 See also :cpp:func:`void simgrid::s4u::Actor::kill(void)`, :cpp:func:`void simgrid::s4u::Actor::kill_all()`,
93 :cpp:func:`simgrid::s4u::this_actor::exit`.
95 .. example-tab:: examples/python/actor-kill/actor-kill.py
97 See also :py:func:`simgrid.Actor.kill`, :py:func:`simgrid.Actor.kill_all`, :py:func:`simgrid.this_actor.exit`.
99 - **Controling the actor life cycle from the XML:**
100 You can specify a start time and a kill time in the deployment file.
104 .. example-tab:: examples/s4u/actor-lifetime/s4u-actor-lifetime.cpp
106 This file is not really interesting: the important matter is in the XML file.
108 .. example-tab:: examples/s4u/actor-lifetime/s4u-actor-lifetime_d.xml
110 This demonstrates the ``start_time`` and ``kill_time`` attribute of the :ref:`pf_tag_actor` tag.
112 - **Daemonize actors:**
113 Some actors may be intended to simulate daemons that run in background. This example show how to transform a regular
114 actor into a daemon that will be automatically killed once the simulation is over.
118 .. example-tab:: examples/s4u/actor-daemon/s4u-actor-daemon.cpp
120 See also :cpp:func:`simgrid::s4u::Actor::daemonize()` and :cpp:func:`simgrid::s4u::Actor::is_daemon()`.
122 .. example-tab:: examples/python/actor-daemon/actor-daemon.py
124 See also :py:func:`simgrid.Actor.daemonize()` and :py:func:`simgrid.Actor.is_daemon()`.
126 Inter-Actors Interactions
127 -------------------------
129 See also the examples on :ref:`inter-actors communications
130 <s4u_ex_communication>` and the ones on :ref:`classical
131 synchronization objects <s4u_ex_IPC>`.
133 - **Suspend and Resume actors:**
134 Actors can be suspended and resumed during their executions.
138 .. example-tab:: examples/s4u/actor-suspend/s4u-actor-suspend.cpp
140 See also :cpp:func:`simgrid::s4u::this_actor::suspend()`,
141 :cpp:func:`simgrid::s4u::Actor::suspend()`, :cpp:func:`simgrid::s4u::Actor::resume()` and
142 :cpp:func:`simgrid::s4u::Actor::is_suspended()`.
144 .. example-tab:: examples/python/actor-suspend/actor-suspend.py
146 See also :py:func:`simgrid.this_actor.suspend()`,
147 :py:func:`simgrid.Actor.suspend()`, :py:func:`simgrid.Actor.resume()` and
148 :py:func:`simgrid.Actor.is_suspended()`.
150 - **Migrating Actors:**
151 Actors can move or be moved from a host to another very easily.
155 .. example-tab:: examples/s4u/actor-migrate/s4u-actor-migrate.cpp
157 See also :cpp:func:`simgrid::s4u::this_actor::migrate()` and :cpp:func:`simgrid::s4u::Actor::migrate()`.
159 .. example-tab:: examples/python/actor-migrate/actor-migrate.py
161 See also :py:func:`simgrid.this_actor.migrate()` and :py:func:`simgrid.Actor.migrate()`.
163 - **Waiting for the termination of an actor:** (joining on it)
164 You can block the current actor until the end of another actor.
168 .. example-tab:: examples/s4u/actor-join/s4u-actor-join.cpp
170 See also :cpp:func:`simgrid::s4u::Actor::join()`.
172 .. example-tab:: examples/python/actor-join/actor-join.py
174 See also :py:func:`simgrid.Actor.join()`.
176 - **Yielding to other actors**.
177 The ```yield()``` function interrupts the execution of the current
178 actor, leaving a chance to the other actors that are ready to run
183 .. example-tab:: examples/s4u/actor-yield/s4u-actor-yield.cpp
185 See also :cpp:func:`simgrid::s4u::this_actor::yield()`.
187 .. example-tab:: examples/python/actor-yield/actor-yield.py
189 See also :py:func:`simgrid.this_actor.yield_()`.
191 Traces Replay as a Workload
192 ---------------------------
194 This section details how to run trace-driven simulations. It is very
195 handy when you want to test an algorithm or protocol that only react
196 to external events. For example, many P2P protocols react to user
197 requests, but do nothing if there is no such event.
199 In such situations, you should write your protocol in C++, and separate
200 the workload that you want to play onto your protocol in a separate
201 text file. Declare a function handling each type of the events in your
202 trace, register them using :cpp:func:`xbt_replay_action_register()` in
203 your main, and then run the simulation.
205 Then, you can either have one trace file containing all your events,
206 or a file per simulated process: the former may be easier to work
207 with, but the second is more efficient on very large traces. Check
208 also the tesh files in the example directories for details.
210 - **Communication replay:**
211 Presents a set of event handlers reproducing classical communication
212 primitives (asynchronous send/receive at the moment).
216 .. example-tab:: examples/s4u/replay-comm/s4u-replay-comm.cpp
219 Presents a set of event handlers reproducing classical I/O
220 primitives (open, read, close).
224 .. example-tab:: examples/s4u/replay-io/s4u-replay-io.cpp
226 ==========================
227 Activities: what Actors do
228 ==========================
230 .. _s4u_ex_communication:
232 Communications on the Network
233 -----------------------------
235 - **Basic asynchronous communications:**
236 Illustrates how to have non-blocking communications, that are
237 communications running in the background leaving the process free
238 to do something else during their completion.
242 .. example-tab:: examples/s4u/async-wait/s4u-async-wait.cpp
244 See also :cpp:func:`simgrid::s4u::Mailbox::put_async()` and :cpp:func:`simgrid::s4u::Comm::wait()`.
246 .. example-tab:: examples/python/async-wait/async-wait.py
248 See also :py:func:`simgrid.Mailbox.put_async()` and :py:func:`simgrid.Comm.wait()`.
250 - **Waiting for all communications in a set:**
251 The ``wait_all()`` function is useful when you want to block until
252 all activities in a given set have completed.
256 .. example-tab:: examples/s4u/async-waitall/s4u-async-waitall.cpp
258 See also :cpp:func:`simgrid::s4u::Comm::wait_all()`.
260 .. example-tab:: examples/python/async-waitall/async-waitall.py
262 See also :py:func:`simgrid.Comm.wait_all()`.
264 - **Waiting for the first completed communication in a set:**
265 The ``wait_any()`` function is useful
266 when you want to block until one activity of the set completes, no
267 matter which terminates first.
271 .. example-tab:: examples/s4u/async-waitany/s4u-async-waitany.cpp
273 See also :cpp:func:`simgrid::s4u::Comm::wait_any()`.
275 .. example-tab:: examples/python/async-waitany/async-waitany.py
277 See also :py:func:`simgrid.Comm.wait_any()`.
279 .. example-tab:: examples/c/async-waitany/async-waitany.c
281 See also :cpp:func:`sg_comm_wait_any`.
283 .. _s4u_ex_execution:
285 Executions on the CPU
286 ---------------------
288 - **Basic execution:**
289 The computations done in your program are not reported to the
290 simulated world, unless you explicitly request the simulator to pause
291 the actor until a given amount of flops gets computed on its simulated
292 host. Some executions can be given an higher priority so that they
297 .. example-tab:: examples/s4u/exec-basic/s4u-exec-basic.cpp
299 See also :cpp:func:`void simgrid::s4u::this_actor::execute(double)`
300 and :cpp:func:`void simgrid::s4u::this_actor::execute(double, double)`.
302 .. example-tab:: examples/python/exec-basic/exec-basic.py
304 See also :py:func:`simgrid.this_actor.execute()`.
306 - **Asynchronous execution:**
307 You can start asynchronous executions, just like you would fire
312 .. example-tab:: examples/s4u/exec-async/s4u-exec-async.cpp
314 See also :cpp:func:`simgrid::s4u::this_actor::exec_init()`,
315 :cpp:func:`simgrid::s4u::Activity::start()`,
316 :cpp:func:`simgrid::s4u::Activity::wait()`,
317 :cpp:func:`simgrid::s4u::Activity::get_remaining()`,
318 :cpp:func:`simgrid::s4u::Exec::get_remaining_ratio()`,
319 :cpp:func:`simgrid::s4u::this_actor::exec_async()` and
320 :cpp:func:`simgrid::s4u::Activity::cancel()`.
322 .. example-tab:: examples/python/exec-async/exec-async.py
324 See also :py:func:`simgrid.this_actor::exec_init()`,
325 :py:func:`simgrid.Activity::start()`,
326 :py:func:`simgrid.Activity.wait()`,
327 :py:func:`simgrid.Activity.get_remaining()`,
328 :py:func:`simgrid.Exec.get_remaining_ratio()`,
329 :py:func:`simgrid.this_actor.exec_async()` and
330 :py:func:`simgrid.Activity.cancel()`.
332 - **Remote execution:**
333 You can start executions on remote hosts, or even change the host
334 on which they occur during their execution.
338 .. example-tab:: examples/s4u/exec-remote/s4u-exec-remote.cpp
340 See also :cpp:func:`simgrid::s4u::Exec::set_host()`.
342 .. example-tab:: examples/python/exec-remote/exec-remote.py
344 See also :py:func:`simgrid.Exec.set_host()`.
346 - **Parallel executions:**
347 These objects are convenient abstractions of parallel
348 computational kernels that span over several machines, such as a
349 PDGEM and the other ScaLAPACK routines. Note that this only works
350 with the "ptask_L07" host model (``--cfg=host/model:ptask_L07``).
354 .. example-tab:: examples/s4u/exec-ptask/s4u-exec-ptask.cpp
356 See also :cpp:func:`simgrid::s4u::this_actor::parallel_execute()`.
358 - **Using Pstates on a host:**
359 This example shows how define a set of pstates in the XML. The current pstate
360 of an host can then be accessed and changed from the program.
364 .. example-tab:: examples/s4u/exec-dvfs/s4u-exec-dvfs.cpp
366 See also :cpp:func:`simgrid::s4u::Host::get_pstate_speed` and :cpp:func:`simgrid::s4u::Host::set_pstate`.
368 .. example-tab:: examples/python/exec-dvfs/exec-dvfs.py
370 See also :py:func:`Host.get_pstate_speed` and :py:func:`Host.set_pstate`.
372 .. example-tab:: examples/platforms/energy_platform.xml
376 I/O on Disks and Files
377 ----------------------
379 SimGrid provides two levels of abstraction to interact with the
380 simulated disks. At the simplest level, you simply create read and
381 write actions on the disk resources.
383 - **Access to raw disk devices:**
384 This example illustrates how to simply read and write data on a
385 simulated disk resource.
389 .. example-tab:: examples/s4u/io-disk-raw/s4u-io-disk-raw.cpp
391 .. example-tab:: examples/platforms/hosts_with_disks.xml
393 This shows how to declare disks in XML.
395 The FileSystem plugin provides a more detailed view, with the
396 classical operations over files: open, move, unlink, and of course
397 read and write. The file and disk sizes are also dealt with and can
398 result in short reads and short write, as in reality.
400 - **File Management:**
401 This example illustrates the use of operations on files
402 (read, write, seek, tell, unlink, etc).
406 .. example-tab:: examples/s4u/io-file-system/s4u-io-file-system.cpp
409 I/O operations on files can also be done in a remote fashion,
410 i.e. when the accessed disk is not mounted on the caller's host.
414 .. example-tab:: examples/s4u/io-file-remote/s4u-io-file-remote.cpp
418 Classical synchronization objects
419 ---------------------------------
422 Shows how to use :cpp:type:`simgrid::s4u::Barrier` synchronization objects.
426 .. example-tab:: examples/s4u/synchro-barrier/s4u-synchro-barrier.cpp
428 - **Condition variable:**
429 Shows how to use :cpp:type:`simgrid::s4u::ConditionVariable` synchronization objects.
433 .. example-tab:: examples/s4u/synchro-condition-variable/s4u-synchro-condition-variable.cpp
436 Shows how to use :cpp:type:`simgrid::s4u::Mutex` synchronization objects.
440 .. example-tab:: examples/s4u/synchro-mutex/s4u-synchro-mutex.cpp
443 Shows how to use :cpp:type:`simgrid::s4u::Semaphore` synchronization objects.
447 .. example-tab:: examples/s4u/synchro-semaphore/s4u-synchro-semaphore.cpp
449 =============================
450 Interacting with the Platform
451 =============================
453 - **User-defined properties:**
454 You can attach arbitrary information to most platform elements from
455 the XML file, and then interact with these values from your
456 program. Note that the changes are not written permanently on disk,
457 in the XML file nor anywhere else. They only last until the end of
462 .. example-tab:: examples/s4u/platform-properties/s4u-platform-properties.cpp
464 - :cpp:func:`simgrid::s4u::Actor::get_property()` and :cpp:func:`simgrid::s4u::Actor::set_property()`
465 - :cpp:func:`simgrid::s4u::Host::get_property()` and :cpp:func:`simgrid::s4u::Host::set_property()`
466 - :cpp:func:`simgrid::s4u::Link::get_property()` and :cpp:func:`simgrid::s4u::Link::set_property()`
467 - :cpp:func:`simgrid::s4u::NetZone::get_property()` and :cpp:func:`simgrid::s4u::NetZone::set_property()`
473 .. showfile:: examples/s4u/platform-properties/s4u-platform-properties_d.xml
479 .. showfile:: examples/platforms/prop.xml
482 - **Retrieving the netzones matching a given criteria:**
483 Shows how to filter the cluster netzones.
487 .. example-tab:: examples/s4u/routing-get-clusters/s4u-routing-get-clusters.cpp
489 - **Retrieving the list of hosts matching a given criteria:**
490 Shows how to filter the actors that match a given criteria.
494 .. example-tab:: examples/s4u/engine-filtering/s4u-engine-filtering.cpp
496 - **Specifying state profiles:** shows how to specify when the
497 resources must be turned off and on again, and how to react to such
498 failures in your code. See also :ref:`howto_churn`.
502 .. example-tab:: examples/s4u/platform-failures/s4u-platform-failures.cpp
506 .. showfile:: examples/platforms/small_platform_failures.xml
509 .. showfile:: examples/platforms/profiles/jupiter_state.profile
511 .. showfile:: examples/platforms/profiles/bourassa_state.profile
513 .. showfile:: examples/platforms/profiles/fafard_state.profile
515 - **Specifying speed profiles:** shows how to specify an external
516 load to resources, variating their peak speed over time.
520 .. example-tab:: examples/s4u/platform-profile/s4u-platform-profile.cpp
524 .. showfile:: examples/platforms/small_platform_profile.xml
527 .. showfile:: examples/platforms/profiles/jupiter_speed.profile
529 .. showfile:: examples/platforms/profiles/link1_bandwidth.profile
531 .. showfile:: examples/platforms/profiles/link1_latency.profile
537 - **Describing the energy profiles in the platform:**
538 This platform file contains the energy profile of each links and
539 hosts, which is necessary to get energy consumption predictions.
540 As usual, you should not trust our example, and you should strive
541 to double-check that your instantiation matches your target platform.
545 .. example-tab:: examples/platforms/energy_platform.xml
547 - **Consumption due to the CPU:**
548 This example shows how to retrieve the amount of energy consumed
549 by the CPU during computations, and the impact of the pstate.
553 .. example-tab:: examples/s4u/energy-exec/s4u-energy-exec.cpp
555 - **Consumption due to the network:**
556 This example shows how to retrieve and display the energy consumed
557 by the network during communications.
561 .. example-tab:: examples/s4u/energy-link/s4u-energy-link.cpp
563 - **Modeling the shutdown and boot of hosts:**
564 Simple example of model of model for the energy consumption during
565 the host boot and shutdown periods.
569 .. example-tab:: examples/s4u/energy-boot/platform_boot.xml
571 .. example-tab:: examples/s4u/energy-boot/s4u-energy-boot.cpp
573 =======================
574 Tracing and Visualizing
575 =======================
577 Tracing can be activated by various configuration options which
578 are illustrated in these example. See also the
579 :ref:`full list of options related to tracing <tracing_tracing_options>`.
581 It is interesting to run the process-create example with the following
582 options to see the task executions:
584 - **Platform Tracing:**
585 This program is a toy example just loading the platform, so that
586 you can play with the platform visualization. Recommanded options:
587 ``--cfg=tracing:yes --cfg=tracing/categorized:yes``
591 .. example-tab:: examples/s4u/trace-platform/s4u-trace-platform.cpp
593 ========================
594 Larger SimGrid Examplars
595 ========================
597 This section contains application examples that are somewhat larger
598 than the previous examples.
601 This simple example just sends one message back and forth.
602 The tesh file laying in the directory show how to start the simulator binary, highlighting how to pass options to
603 the simulators (as detailed in Section :ref:`options`).
607 .. example-tab:: examples/s4u/app-pingpong/s4u-app-pingpong.cpp
610 Shows how to implement a classical communication pattern, where a
611 token is exchanged along a ring to reach every participant.
615 .. example-tab:: examples/s4u/app-token-ring/s4u-app-token-ring.cpp
617 - **Master Workers:**
618 Another good old example, where one Master process has a bunch of task to dispatch to a set of several Worker
625 This example comes in two equivalent variants, one where the actors
626 are specified as simple functions (which is easier to understand for
627 newcomers) and one where the actors are specified as classes (which is
628 more powerful for the users wanting to build their own projects upon
631 .. showfile:: examples/s4u/app-masterworkers/s4u-app-masterworkers-class.cpp
634 .. showfile:: examples/s4u/app-masterworkers/s4u-app-masterworkers-fun.cpp
641 Classical protocol for Peer-to-Peer data diffusion.
647 .. showfile:: examples/s4u/app-bittorrent/s4u-bittorrent.cpp
650 .. showfile:: examples/s4u/app-bittorrent/s4u-peer.cpp
653 .. showfile:: examples/s4u/app-bittorrent/s4u-tracker.cpp
657 Data broadcast over a ring of processes.
661 .. example-tab:: examples/s4u/app-chainsend/s4u-app-chainsend.cpp
663 Distributed Hash Tables (DHT)
664 -----------------------------
667 One of the most famous DHT protocol.
673 .. showfile:: examples/s4u/dht-chord/s4u-dht-chord.cpp
676 .. showfile:: examples/s4u/dht-chord/s4u-dht-chord-node.cpp
680 Another well-known DHT protocol.
686 .. showfile:: examples/s4u/dht-kademlia/s4u-dht-kademlia.cpp
689 .. showfile:: examples/s4u/dht-kademlia/routing_table.cpp
692 .. showfile:: examples/s4u/dht-kademlia/answer.cpp
695 .. showfile:: examples/s4u/dht-kademlia/node.cpp
704 This example starts some computations both on PMs and VMs, and
705 migrates some VMs around.
709 .. example-tab:: examples/s4u/cloud-simple/s4u-cloud-simple.cpp
712 This example shows how to migrate VMs between PMs.
716 .. example-tab:: examples/s4u/cloud-migration/s4u-cloud-migration.cpp
718 =======================
719 Model-Checking Examples
720 =======================
722 The model-checker can be used to exhaustively search for issues in the
723 tested application. It must be activated at compile time, but this
724 mode is rather experimental in SimGrid (as of v3.22). You should not
725 enable it unless you really want to formally verify your applications:
726 SimGrid is slower and maybe less robust when MC is enabled.
729 In this example, two actors send some data to a central server,
730 which asserts that the messages are always received in the same order.
731 This is obviously wrong, and the model-checker correctly finds a
732 counter-example to that assertion.
736 .. example-tab:: examples/s4u/mc-failing-assert/s4u-mc-failing-assert.cpp
742 .. |cpp| image:: /img/lang_cpp.png
746 .. |py| image:: /img/lang_python.png