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.
11 SimGrid comes with an extensive set of examples, documented on this
12 page. Most of them only demonstrate one single feature, with some
13 larger exemplars listed below.
15 The C++ examples can be found under examples/cpp while python examples
16 are in examples/python. Each such directory contains the source code (also listed
17 from this page), and the so-called tesh file containing how to call
18 the binary obtained by compiling this example and also the expected
19 output. Tesh files are used to turn each of our examples into an
20 integration test. Some examples also contain other files, on need.
22 A good way to bootstrap your own project is to copy and combine some
23 of the provided examples to constitute the skeleton of what you plan
28 ***************************
29 Actors: the Active Entities
30 ***************************
32 Starting and Stopping Actors
33 ============================
35 .. _s4u_ex_actors_create:
40 Most actors are started from the deployment XML file because this
41 is a :ref:`better scientific habit <howto_science>`, but you can
42 also create them directly from your code.
46 .. example-tab:: examples/cpp/actor-create/s4u-actor-create.cpp
48 You create actors either:
50 - Directly with :cpp:func:`simgrid::s4u::Actor::create`
51 - From XML with :cpp:func:`simgrid::s4u::Engine::register_actor` (if your actor is a class)
52 or :cpp:func:`simgrid::s4u::Engine::register_function` (if your actor is a function)
53 and then :cpp:func:`simgrid::s4u::Engine::load_deployment`
55 .. example-tab:: examples/python/actor-create/actor-create.py
57 You create actors either:
59 - Directly with :py:func:`simgrid.Actor.create()`
60 - From XML with :py:func:`simgrid.Engine.register_actor()` and then :py:func:`simgrid.Engine.load_deployment()`
62 .. example-tab:: examples/c/actor-create/actor-create.c
64 You create actors either:
66 - Directly with :cpp:func:`sg_actor_create` followed by :cpp:func:`sg_actor_start`.
67 - From XML with :cpp:func:`simgrid_register_function` and then :cpp:func:`simgrid_load_deployment`.
69 .. example-tab:: examples/python/actor-create/actor-create_d.xml
71 The following file is used in both C++ and Python.
73 Reacting to actors' end
74 -----------------------
76 You can attach callbacks to the end of actors. There are several ways of doing so, depending on whether you want to
77 attach your callback to a given actor and on how you define the end of a
78 given actor. User code probably wants to react to the termination of an actor
79 while some plugins want to react to the destruction (memory collection) of
84 .. example-tab:: examples/cpp/actor-exiting/s4u-actor-exiting.cpp
86 This example shows how to attach a callback to:
88 - the end of a specific actor: :cpp:func:`simgrid::s4u::Actor::on_exit()`
89 - the end of any actor: :cpp:func:`simgrid::s4u::Actor::on_termination_cb`
90 - the destruction of any actor: :cpp:func:`simgrid::s4u::Actor::on_destruction_cb`
92 .. example-tab:: examples/c/actor-exiting/actor-exiting.c
94 This example shows how to attach a callback to the end of a specific actor with
95 :cpp:func:`sg_actor_on_exit()`.
100 Actors can forcefully stop other actors.
104 .. example-tab:: examples/cpp/actor-kill/s4u-actor-kill.cpp
106 See also :cpp:func:`void simgrid::s4u::Actor::kill(void)`, :cpp:func:`void simgrid::s4u::Actor::kill_all()`,
107 :cpp:func:`simgrid::s4u::this_actor::exit`, :cpp:func:`simgrid::s4u::Actor::on_exit`.
109 .. example-tab:: examples/python/actor-kill/actor-kill.py
111 See also :py:func:`simgrid.Actor.kill()`, :py:func:`simgrid.Actor.kill_all()`, :py:func:`simgrid.this_actor.exit()`,
112 :py:func:`simgrid.this_actor.on_exit`.
114 .. example-tab:: examples/c/actor-kill/actor-kill.c
116 See also :cpp:func:`sg_actor_kill`, :cpp:func:`sg_actor_kill_all`, :cpp:func:`sg_actor_exit`, :cpp:func:`sg_actor_on_exit`.
118 Actors' life cycle from XML_reference
119 -------------------------------------
121 You can specify a start time and a kill time in the deployment file.
125 .. example-tab:: examples/cpp/actor-lifetime/s4u-actor-lifetime.cpp
127 This file is not really interesting: the important matter is in the XML file.
129 .. example-tab:: examples/cpp/actor-lifetime/s4u-actor-lifetime_d.xml
131 This demonstrates the ``start_time`` and ``kill_time`` attribute of the :ref:`pf_tag_actor` tag.
133 .. example-tab:: examples/python/actor-lifetime/actor-lifetime.py
135 This file is not really interesting: the important matter is in the XML file.
137 .. example-tab:: examples/c/actor-lifetime/actor-lifetime.c
139 This file is not really interesting: the important matter is in the XML file.
144 Some actors may be intended to simulate daemons that run in the background.
145 This example shows how to transform a regular
146 actor into a daemon that will be automatically killed once the simulation is over.
150 .. example-tab:: examples/cpp/actor-daemon/s4u-actor-daemon.cpp
152 See also :cpp:func:`simgrid::s4u::Actor::daemonize()` and :cpp:func:`simgrid::s4u::Actor::is_daemon()`.
154 .. example-tab:: examples/python/actor-daemon/actor-daemon.py
156 See also :py:func:`simgrid.Actor.daemonize()` and :py:func:`simgrid.Actor.is_daemon()`.
158 .. example-tab:: examples/c/actor-daemon/actor-daemon.c
160 See also :cpp:func:`sg_actor_daemonize` and :cpp:func:`sg_actor_is_daemon`.
162 Specifying the stack size
163 -------------------------
165 The stack size can be specified by default on the command line,
166 globally by changing the configuration with :cpp:func:`simgrid::s4u::Engine::set_config`,
167 or for a specific actor using :cpp:func:`simgrid::s4u::Actor::set_stacksize` before its start.
171 .. example-tab:: examples/cpp/actor-stacksize/s4u-actor-stacksize.cpp
173 .. example-tab:: examples/c/actor-stacksize/actor-stacksize.c
175 Inter-Actors Interactions
176 =========================
178 See also the examples on :ref:`inter-actors communications
179 <s4u_ex_communication>` and the ones on :ref:`classical
180 synchronization objects <s4u_ex_IPC>`.
182 Suspending/resuming Actors
183 --------------------------
185 Actors can be suspended and resumed during their executions.
189 .. example-tab:: examples/cpp/actor-suspend/s4u-actor-suspend.cpp
191 See also :cpp:func:`simgrid::s4u::this_actor::suspend()`,
192 :cpp:func:`simgrid::s4u::Actor::suspend()`, :cpp:func:`simgrid::s4u::Actor::resume()`, and
193 :cpp:func:`simgrid::s4u::Actor::is_suspended()`.
195 .. example-tab:: examples/python/actor-suspend/actor-suspend.py
197 See also :py:func:`simgrid.this_actor.suspend()`,
198 :py:func:`simgrid.Actor.suspend()`, :py:func:`simgrid.Actor.resume()`, and
199 :py:func:`simgrid.Actor.is_suspended()`.
201 .. example-tab:: examples/c/actor-suspend/actor-suspend.c
203 See also :cpp:func:`sg_actor_suspend()`, :cpp:func:`sg_actor_resume()`, and
204 :cpp:func:`sg_actor_is_suspended()`.
209 Actors can move or be moved from a host to another very easily. It amounts to setting them on a new host.
213 .. example-tab:: examples/cpp/actor-migrate/s4u-actor-migrate.cpp
215 See also :cpp:func:`simgrid::s4u::this_actor::set_host()` and :cpp:func:`simgrid::s4u::Actor::set_host()`.
217 .. example-tab:: examples/python/actor-migrate/actor-migrate.py
219 See also :py:attr:`simgrid.Actor.host`.
221 .. example-tab:: examples/c/actor-migrate/actor-migrate.c
223 See also :cpp:func:`sg_actor_set_host()`.
225 Waiting for the termination of an actor (joining on it)
226 -------------------------------------------------------
228 You can block the current actor until the end of another actor.
232 .. example-tab:: examples/cpp/actor-join/s4u-actor-join.cpp
234 See also :cpp:func:`simgrid::s4u::Actor::join()`.
236 .. example-tab:: examples/python/actor-join/actor-join.py
238 See also :py:func:`simgrid.Actor.join()`.
240 .. example-tab:: examples/c/actor-join/actor-join.c
242 See also :cpp:func:`sg_actor_join`.
244 Yielding to other actors
245 ------------------------
247 The ```yield()``` function interrupts the execution of the current
248 actor, leaving a chance to the other actors that are ready to run
253 .. example-tab:: examples/cpp/actor-yield/s4u-actor-yield.cpp
255 See also :cpp:func:`simgrid::s4u::this_actor::yield()`.
257 .. example-tab:: examples/python/actor-yield/actor-yield.py
259 See also :py:func:`simgrid.this_actor.yield_()`.
261 .. example-tab:: examples/c/actor-yield/actor-yield.c
263 See also :cpp:func:`sg_actor_yield()`.
265 Traces Replay as a Workload
266 ===========================
268 This section details how to run trace-driven simulations. It is very
269 handy when you want to test an algorithm or protocol that only reacts
270 to external events. For example, many P2P protocols react to user
271 requests, but do nothing if there is no such event.
273 In such situations, you should write your protocol in C++, and separate
274 the workload that you want to play onto your protocol in a separate
275 text file. Declare a function handling each type of the events in your
276 trace, register them using :cpp:func:`xbt_replay_action_register()` in
277 your main, and then run the simulation.
279 Then, you can either have one trace file containing all your events,
280 or a file per simulated process: the former may be easier to work
281 with, but the second is more efficient on very large traces. Check
282 also the tesh files in the example directories for details.
287 Presents a set of event handlers reproducing classical communication primitives (asynchronous send/receive at the moment).
291 .. example-tab:: examples/cpp/replay-comm/s4u-replay-comm.cpp
296 Presents a set of event handlers reproducing classical I/O primitives (open, read, close).
300 .. example-tab:: examples/cpp/replay-io/s4u-replay-io.cpp
302 **************************
303 Activities: what Actors do
304 **************************
306 .. _s4u_ex_communication:
308 Communications on the Network
309 =============================
314 This simple example just sends one message back and forth.
315 The tesh file laying in the directory shows how to start the simulator binary, highlighting how to pass options to
316 the simulators (as detailed in Section :ref:`options`).
320 .. example-tab:: examples/cpp/comm-pingpong/s4u-comm-pingpong.cpp
322 .. example-tab:: examples/python/comm-pingpong/comm-pingpong.py
324 .. example-tab:: examples/c/comm-pingpong/comm-pingpong.c
326 Basic asynchronous communications
327 ---------------------------------
329 Illustrates how to have non-blocking communications, that are communications running in the background leaving the process
330 free to do something else during their completion.
334 .. example-tab:: examples/cpp/comm-wait/s4u-comm-wait.cpp
336 See also :cpp:func:`simgrid::s4u::Mailbox::put_async()` and :cpp:func:`simgrid::s4u::Comm::wait()`.
338 .. example-tab:: examples/python/comm-wait/comm-wait.py
340 See also :py:func:`simgrid.Mailbox.put_async()` and :py:func:`simgrid.Comm.wait()`.
342 .. example-tab:: examples/c/comm-wait/comm-wait.c
344 See also :cpp:func:`sg_mailbox_put_async()` and :cpp:func:`sg_comm_wait()`.
346 Waiting for communications with timeouts
347 ----------------------------------------
349 There is two ways of declaring timeouts in SimGrid. ``waituntil`` let you specify the deadline until when you want to wait, while
350 ``waitfor`` expects the maximal wait duration.
351 This example is very similar to the previous one, simply adding how to declare timeouts when waiting on asynchronous communication.
355 .. example-tab:: examples/cpp/comm-waituntil/s4u-comm-waituntil.cpp
357 See also :cpp:func:`simgrid::s4u::Activity::wait_until()` and :cpp:func:`simgrid::s4u::Comm::wait_for()`.
359 .. example-tab:: examples/python/comm-waituntil/comm-waituntil.py
361 See also :py:func:`simgrid.Comm.wait_until()`
363 .. _s4u_ex_mailbox_ready:
365 Checking for incoming communications
366 ------------------------------------
368 This example uses ``Mailbox.ready()`` to check for completed communications. When this function returns true, then at least a message
369 is arrived, so you know that ``Mailbox.get()`` will complete imediately. This is thus another way toward asynchronous communications.
373 .. example-tab:: examples/cpp/comm-ready/s4u-comm-ready.cpp
375 See also :cpp:func:`simgrid::s4u::Mailbox::ready()`.
377 .. example-tab:: examples/python/comm-ready/comm-ready.py
379 See also :py:func:`simgrid.Mailbox.ready()`
382 Suspending communications
383 -------------------------
385 The ``suspend()`` and ``resume()`` functions block the progression of a given communication for a while and then unblock it.
386 ``is_suspended()`` returns whether that activity is currently blocked or not.
390 .. example-tab:: examples/cpp/comm-suspend/s4u-comm-suspend.cpp
392 See also :cpp:func:`simgrid::s4u::Activity::suspend()`
393 :cpp:func:`simgrid::s4u::Activity::resume()` and
394 :cpp:func:`simgrid::s4u::Activity::is_suspended()`.
396 .. example-tab:: examples/python/comm-suspend/comm-suspend.py
398 See also :py:func:`simgrid.Comm.suspend()` and
399 :py:func:`simgrid.Comm.resume()`.
401 Waiting for all communications in a set
402 ---------------------------------------
404 The ``wait_all()`` function is useful when you want to block until all activities in a given set have been completed.
408 .. example-tab:: examples/cpp/comm-waitall/s4u-comm-waitall.cpp
410 See also :cpp:func:`simgrid::s4u::Comm::wait_all()`.
412 .. example-tab:: examples/python/comm-waitall/comm-waitall.py
414 See also :py:func:`simgrid.Comm.wait_all()`.
416 .. example-tab:: examples/c/comm-waitall/comm-waitall.c
418 See also :cpp:func:`sg_comm_wait_all()`.
420 Waiting for the first completed communication in a set
421 ------------------------------------------------------
423 The ``wait_any()`` blocks until one activity of the set completes, no matter which terminates first.
427 .. example-tab:: examples/cpp/comm-waitany/s4u-comm-waitany.cpp
429 See also :cpp:func:`simgrid::s4u::Comm::wait_any()`.
431 .. example-tab:: examples/python/comm-waitany/comm-waitany.py
433 See also :py:func:`simgrid.Comm.wait_any()`.
435 .. example-tab:: examples/c/comm-waitany/comm-waitany.c
437 See also :cpp:func:`sg_comm_wait_any`.
439 Testing whether at least one communication completed
440 ----------------------------------------------------
442 The ``test_any()`` returns whether at least one activity of the set has completed, or -1.
446 .. example-tab:: examples/cpp/comm-testany/s4u-comm-testany.cpp
448 See also :cpp:func:`simgrid::s4u::Comm::test_any()`.
450 .. example-tab:: examples/python/comm-testany/comm-testany.py
452 See also :py:func:`simgrid.Comm.test_any()`.
454 .. _s4u_ex_comm_failure:
456 Dealing with network failures
457 -----------------------------
459 This examples shows how to survive to network exceptions that occurs when a link is turned off, or when the actor with whom
460 you communicate fails because its host is turned off. In this case, any blocking operation such as ``put``, ``get`` or
461 ``wait`` will raise an exception that you can catch and react to. See also :ref:`howto_churn`,
462 :ref:`this example <s4u_ex_platform_state_profile>` on how to attach a state profile to hosts and
463 :ref:`that example <s4u_ex_exec_failure>` on how to react to host failures.
467 .. example-tab:: examples/cpp/comm-failure/s4u-comm-failure.cpp
469 .. example-tab:: examples/python/comm-failure/comm-failure.py
471 .. _s4u_ex_comm_host2host:
473 Direct host-to-host communication
474 ---------------------------------
476 This example demonstrates the direct communication mechanism, that allows to send data from one host to another without
477 relying on the mailbox mechanism.
481 .. example-tab:: examples/cpp/comm-host2host/s4u-comm-host2host.cpp
483 See also :cpp:func:`simgrid::s4u::Comm::sendto_init()` and :cpp:func:`simgrid::s4u::Comm::sendto_async()`.
485 .. example-tab:: examples/python/comm-host2host/comm-host2host.py
487 See also :py:func:`simgrid.Comm.sendto_init()` and :py:func:`simgrid.Comm.sendto_async()`.
489 .. _s4u_ex_execution:
491 Executions on the CPU
492 =====================
497 The computations done in your program are not reported to the
498 simulated world unless you explicitly request the simulator to pause
499 the actor until a given amount of flops gets computed on its simulated
500 host. Some executions can be given a higher priority so that they
505 .. example-tab:: examples/cpp/exec-basic/s4u-exec-basic.cpp
507 See also :cpp:func:`void simgrid::s4u::this_actor::execute(double)`
508 and :cpp:func:`void simgrid::s4u::this_actor::execute(double, double)`.
510 .. example-tab:: examples/python/exec-basic/exec-basic.py
512 See also :py:func:`simgrid.this_actor.execute()`.
514 .. example-tab:: examples/c/exec-basic/exec-basic.c
516 See also :cpp:func:`void sg_actor_execute(double)`
517 and :cpp:func:`void sg_actor_execute_with_priority(double, double)`.
519 Asynchronous execution
520 ----------------------
522 You can start asynchronous executions, just like you would fire background threads.
526 .. example-tab:: examples/cpp/exec-async/s4u-exec-async.cpp
528 See also :cpp:func:`simgrid::s4u::this_actor::exec_init()`,
529 :cpp:func:`simgrid::s4u::Activity::start()`,
530 :cpp:func:`simgrid::s4u::Activity::wait()`,
531 :cpp:func:`simgrid::s4u::Activity::get_remaining()`,
532 :cpp:func:`simgrid::s4u::Exec::get_remaining_ratio()`,
533 :cpp:func:`simgrid::s4u::this_actor::exec_async()` and
534 :cpp:func:`simgrid::s4u::Activity::cancel()`.
536 .. example-tab:: examples/python/exec-async/exec-async.py
538 See also :py:func:`simgrid.this_actor.exec_init()`,
539 :py:func:`simgrid.Exec.start()`,
540 :py:func:`simgrid.Exec.wait()`,
541 :py:attr:`simgrid.Exec.remaining`,
542 :py:attr:`simgrid.Exec.remaining_ratio`,
543 :py:func:`simgrid.this_actor.exec_async()` and
544 :py:func:`simgrid.Exec.cancel()`.
546 .. example-tab:: examples/c/exec-async/exec-async.c
548 See also :cpp:func:`sg_actor_exec_init()`,
549 :cpp:func:`sg_exec_start()`,
550 :cpp:func:`sg_exec_wait()`,
551 :cpp:func:`sg_exec_get_remaining()`,
552 :cpp:func:`sg_exec_get_remaining_ratio()`,
553 :cpp:func:`sg_actor_exec_async()` and
554 :cpp:func:`sg_exec_cancel()`,
559 You can start executions on remote hosts, or even change the host on which they occur during their execution.
560 This is naturally not very realistic, but it's something handy to have.
564 .. example-tab:: examples/cpp/exec-remote/s4u-exec-remote.cpp
566 See also :cpp:func:`simgrid::s4u::Exec::set_host()`.
568 .. example-tab:: examples/python/exec-remote/exec-remote.py
570 See also :py:attr:`simgrid.Exec.host`.
572 .. example-tab:: examples/c/exec-remote/exec-remote.c
574 See also :cpp:func:`sg_exec_set_host()`.
581 These objects are convenient abstractions of parallel
582 computational kernels that span over several machines, such as a
583 PDGEM and the other ScaLAPACK routines. Note that this only works
584 with the "ptask_L07" host model (``--cfg=host/model:ptask_L07``).
586 This example demonstrates several kinds of parallel tasks: regular
587 ones, communication-only (without computation), computation-only
588 (without communication), synchronization-only (neither
589 communication nor computation). It also shows how to reconfigure a
590 task after its start, to change the number of hosts it runs onto.
591 This allows simulating malleable tasks.
595 .. example-tab:: examples/cpp/exec-ptask/s4u-exec-ptask.cpp
597 See also :cpp:func:`simgrid::s4u::this_actor::parallel_execute()`.
599 .. example-tab:: examples/python/exec-ptask/exec-ptask.py
601 See also :ref:`simgrid.this_actor.parallel_execute()`
603 Ptasks play well with the host energy plugin, as shown in this example.
604 There is not much new compared to the above ptask example or the
605 :ref:`examples about energy <s4u_ex_energy>`. It just works.
609 .. example-tab:: examples/cpp/energy-exec-ptask/s4u-energy-exec-ptask.cpp
611 .. example-tab:: examples/c/energy-exec-ptask/energy-exec-ptask.c
613 .. _s4u_ex_exec_failure:
615 Dealing with host failures
616 --------------------------
618 This examples shows how to survive to host failure exceptions that occur when an host is turned off. The actors do not get notified when the host
619 on which they run is turned off: they are just terminated in this case, and their ``on_exit()`` callback gets executed. For remote executions on
620 failing hosts however, any blocking operation such as ``exec`` or ``wait`` will raise an exception that you can catch and react to. See also
622 :ref:`this example <s4u_ex_platform_state_profile>` on how to attach a state profile to hosts, and
623 :ref:`that example <s4u_ex_comm_failure>` on how to react to networ failures.
627 .. example-tab:: examples/cpp/exec-failure/s4u-exec-failure.cpp
634 This example shows how to define a set of pstates in the XML. The current pstate
635 of a host can then be accessed and changed from the program.
639 .. example-tab:: examples/cpp/exec-dvfs/s4u-exec-dvfs.cpp
641 See also :cpp:func:`simgrid::s4u::Host::get_pstate_speed` and :cpp:func:`simgrid::s4u::Host::set_pstate`.
643 .. example-tab:: examples/c/exec-dvfs/exec-dvfs.c
645 See also :cpp:func:`sg_host_get_pstate_speed` and :cpp:func:`sg_host_set_pstate`.
647 .. example-tab:: examples/python/exec-dvfs/exec-dvfs.py
649 See also :py:func:`simgrid.Host.pstate_speed()` and :py:attr:`simgrid.Host.pstate`.
651 .. example-tab:: examples/platforms/energy_platform.xml
653 The important parts are in the :ref:`pf_tag_host` tag. The ``pstate`` attribute is the initial pstate while the ``speed`` attribute must
654 be a comma-separated list of values: the speed at each pstate. This platform file also describes the ``wattage_per_state`` and
655 ``wattage_off`` properties, that are used by the :ref:`plugin_host_energy` plugin.
659 I/O on Disks and Files
660 ======================
662 SimGrid provides two levels of abstraction to interact with the
663 simulated disks. At the simplest level, you simply create read and
664 write actions on the disk resources.
666 Access to raw disk devices
667 --------------------------
669 This example illustrates how to simply read and write data on a simulated disk resource.
673 .. example-tab:: examples/cpp/io-disk-raw/s4u-io-disk-raw.cpp
675 .. example-tab:: examples/c/io-disk-raw/io-disk-raw.c
677 .. example-tab:: examples/platforms/hosts_with_disks.xml
679 This shows how to declare disks in XML.
681 Asynchronous raw accesses
682 -------------------------
684 As most other activities, raw IO accesses can be used asynchronously, as illustrated in this example.
688 .. example-tab:: examples/cpp/io-async/s4u-io-async.cpp
693 The FileSystem plugin provides a more detailed view, with the
694 classical operations over files: open, move, unlink, and of course,
695 read and write. The file and disk sizes are also dealt with and can
696 result in short reads and short writes, as in reality.
698 - **File Management:**
699 This example illustrates the use of operations on files
700 (read, write, seek, tell, unlink, etc).
704 .. example-tab:: examples/cpp/io-file-system/s4u-io-file-system.cpp
706 .. example-tab:: examples/c/io-file-system/io-file-system.c
709 I/O operations on files can also be done remotely,
710 i.e. when the accessed disk is not mounted on the caller's host.
714 .. example-tab:: examples/cpp/io-file-remote/s4u-io-file-remote.cpp
716 .. example-tab:: examples/c/io-file-remote/io-file-remote.c
720 Dependencies between activities
721 ===============================
723 SimGrid makes it easy to express dependencies between activities, where a given activity cannot start until the completion of
724 all its predecessors. You can even have simulation not involving any actors, where the main thread (called maestro) creates and
725 schedules activities itself.
730 When you declare dependencies between two activities, the depedent will not actually start until all its dependencies complete,
731 as shown in the following examples. The first one declare dependencies between executions while the second one declare
732 dependencies between communications. You could declare such dependencies between arbitrary activities.
736 .. example-tab:: examples/cpp/exec-dependent/s4u-exec-dependent.cpp
740 .. example-tab:: examples/cpp/comm-dependent/s4u-comm-dependent.cpp
745 To actually start, an activity needs to be assigned to a given resource. This examples illustrates how an execution that is not
746 assigned will not actually start until being assigned. In some sense, activities' assignment can be seen as a specific
747 dependency that can withdraw their execution.
751 .. example-tab:: examples/cpp/exec-unassigned/s4u-exec-unassigned.cpp
753 Simple DAG of activities
754 ------------------------
756 This example shows how to create activities from the maestro directly without relying on an actor, organize the dependencies of
757 activities as a DAG (direct acyclic graph), and start them. Each activity will start as soon as its dependencies are fullfiled.
761 .. example-tab:: examples/cpp/dag-simple/s4u-dag-simple.cpp
763 DAG with communication
764 ----------------------
766 This is a little example showing how add communication activities to your DAG, representing inter-task data exchanges.
770 .. example-tab:: examples/cpp/dag-comm/s4u-dag-comm.cpp
775 This is a little example showing how add I/O activities to your DAG, representing disk buffers.
779 .. example-tab:: examples/cpp/dag-io/s4u-dag-io.cpp
781 Scheduling activities
782 ---------------------
784 This example illustrates a simple scheduling algorithm, where the activities are placed on the "most adapted" host. Of course, there is many way
785 to determine which host is the better fit for a given activity, and this example just uses a simple algorithm.
789 .. example-tab:: examples/cpp/dag-scheduling/s4u-dag-scheduling.cpp
791 Loading DAGs from file
792 ----------------------
794 There is currently two file formats that you can load directly in SimGrid, but writting another loader for your beloved format should not be difficult.
798 .. example-tab:: examples/cpp/dag-from-dax/s4u-dag-from-dax.cpp
802 .. showfile:: examples/cpp/dag-from-dax/smalldax.xml
807 .. example-tab:: examples/cpp/dag-from-dot/s4u-dag-from-dot.cpp
811 .. showfile:: examples/cpp/dag-from-dot/dag.dot
814 Simulating a time slice
815 -----------------------
817 When you declare activities, :cpp:func:`simgrid::s4u::Engine::run()` runs up to the point of time where an activity completes.
818 Sometimes, you want to give a maximal duration to simulate up to a given date at most, for example to inject a new activity at that time.
819 This example shows how to do it.
823 .. example-tab:: examples/cpp/engine-run-partial/s4u-engine-run-partial.cpp
828 This example shows how to deal with host or network failures while scheduling DAGs of activities.
832 .. example-tab:: examples/cpp/dag-failure/s4u-dag-failure.cpp
836 Classical synchronization objects
837 =================================
842 Shows how to use :cpp:type:`simgrid::s4u::Barrier` synchronization objects.
846 .. example-tab:: examples/cpp/synchro-barrier/s4u-synchro-barrier.cpp
848 .. example-tab:: examples/python/synchro-barrier/synchro-barrier.py
850 Condition variable: basic usage
851 -------------------------------
853 Shows how to use :cpp:type:`simgrid::s4u::ConditionVariable` synchronization objects.
857 .. example-tab:: examples/cpp/synchro-condition-variable/s4u-synchro-condition-variable.cpp
859 Condition variable: timeouts
860 ----------------------------
862 Shows how to specify timeouts when blocking on condition variables.
866 .. example-tab:: examples/cpp/synchro-condition-variable-waituntil/s4u-synchro-condition-variable-waituntil.cpp
871 Shows how to use :cpp:type:`simgrid::s4u::Mutex` synchronization objects.
875 .. example-tab:: examples/cpp/synchro-mutex/s4u-synchro-mutex.cpp
877 .. example-tab:: examples/python/synchro-mutex/synchro-mutex.py
882 Shows how to use :cpp:type:`simgrid::s4u::Semaphore` synchronization objects.
886 .. example-tab:: examples/cpp/synchro-semaphore/s4u-synchro-semaphore.cpp
888 .. example-tab:: examples/python/synchro-semaphore/synchro-semaphore.py
890 .. example-tab:: examples/c/synchro-semaphore/synchro-semaphore.c
892 *****************************
893 Interacting with the Platform
894 *****************************
896 User-defined properties
897 =======================
899 You can attach arbitrary information to most platform elements from the XML file, and then interact with these values from your
900 program. Note that the changes are not written permanently on disk, in the XML file nor anywhere else. They only last until the end of
905 .. example-tab:: examples/cpp/platform-properties/s4u-platform-properties.cpp
907 - :cpp:func:`simgrid::s4u::Actor::get_property()` and :cpp:func:`simgrid::s4u::Actor::set_property()`
908 - :cpp:func:`simgrid::s4u::Host::get_property()` and :cpp:func:`simgrid::s4u::Host::set_property()`
909 - :cpp:func:`simgrid::s4u::Link::get_property()` and :cpp:func:`simgrid::s4u::Link::set_property()`
910 - :cpp:func:`simgrid::s4u::NetZone::get_property()` and :cpp:func:`simgrid::s4u::NetZone::set_property()`
912 .. example-tab:: examples/c/platform-properties/platform-properties.c
914 - :cpp:func:`sg_actor_get_property_value()`
915 - :cpp:func:`sg_host_get_property_value()` and :cpp:func:sg_host_set_property_value()`
916 - :cpp:func:`sg_zone_get_property_value()` and :cpp:func:`sg_zone_set_property_value()`
922 .. showfile:: examples/platforms/prop.xml
928 Retrieving the netzones matching given criteria
929 -----------------------------------------------
931 Shows how to filter the cluster netzones.
935 .. example-tab:: examples/cpp/routing-get-clusters/s4u-routing-get-clusters.cpp
937 Retrieving the list of hosts matching given criteria
938 ----------------------------------------------------
940 Shows how to filter the actors that match given criteria.
944 .. example-tab:: examples/cpp/engine-filtering/s4u-engine-filtering.cpp
949 .. _s4u_ex_platform_state_profile:
951 Specifying state profiles
952 -------------------------
954 Shows how to specify when the resources must be turned off and on again, and how to react to such
955 failures in your code. See also :ref:`howto_churn`,
956 :ref:`this example <s4u_ex_comm_failure>` on how to react to communication failures, and
957 :ref:`that example <s4u_ex_exec_failure>` on how to react to host failures.
961 .. example-tab:: examples/cpp/platform-failures/s4u-platform-failures.cpp
963 .. example-tab:: examples/c/platform-failures/platform-failures.c
965 .. example-tab:: examples/python/platform-failures/platform-failures.py
969 .. showfile:: examples/platforms/small_platform_failures.xml
972 .. showfile:: examples/platforms/profiles/jupiter_state.profile
974 .. showfile:: examples/platforms/profiles/fafard_state.profile
976 Specifying speed profiles
977 -------------------------
979 Shows how to specify an external load to resources, variating their peak speed over time.
983 .. example-tab:: examples/cpp/platform-profile/s4u-platform-profile.cpp
985 .. example-tab:: examples/python/platform-profile/platform-profile.py
989 .. showfile:: examples/platforms/small_platform_profile.xml
992 .. showfile:: examples/platforms/profiles/jupiter_speed.profile
994 .. showfile:: examples/platforms/profiles/link1_bandwidth.profile
996 .. showfile:: examples/platforms/profiles/link1_latency.profile
998 Modifying the platform
999 ======================
1001 Serializing communications
1002 --------------------------
1004 This example shows how to limit the amount of communications going through a given link.
1005 It is very similar to the other asynchronous communication examples, but messages get serialized by the platform.
1006 Without this call to ``Link::set_concurrency_limit(2)``, all messages would be received at the exact same timestamp since
1007 they are initiated at the same instant and are of the same size. But with this extra configuration to the link, at most 2
1008 messages can travel through the link at the same time.
1012 .. example-tab:: examples/cpp/platform-comm-serialize/s4u-platform-comm-serialize.cpp
1014 See also :cpp:func:`simgrid::s4u::Link::set_concurrency_limit()`.
1016 .. example-tab:: examples/python/platform-comm-serialize/platform-comm-serialize.py
1018 See also :py:func:`simgrid.Link.set_concurrency_limit()`.
1029 Describing the energy profiles in the platform
1030 ----------------------------------------------
1032 The first platform file contains the energy profile of each link and host for a wired network, which is necessary to get energy consumption
1033 predictions. The second platform file is the equivalent for a wireless network. As usual, you should not trust our example, and you should
1034 strive to double-check that your instantiation matches your target platform.
1040 .. showfile:: examples/platforms/energy_platform.xml
1043 .. showfile:: examples/platforms/wifi_energy.xml
1049 CPU energy consumption
1050 ----------------------
1052 This example shows how to retrieve the amount of energy consumed by the CPU during computations, and the impact of the pstate.
1056 .. example-tab:: examples/cpp/energy-exec/s4u-energy-exec.cpp
1058 .. example-tab:: examples/c/energy-exec/energy-exec.c
1060 Virtual machines consumption
1061 ----------------------------
1063 This example is very similar to the previous one, adding VMs to the picture.
1067 .. example-tab:: examples/cpp/energy-vm/s4u-energy-vm.cpp
1069 .. example-tab:: examples/c/energy-vm/energy-vm.c
1071 Wired network energy consumption
1072 --------------------------------
1074 This example shows how to retrieve and display the energy consumed by the wired network during communications.
1078 .. example-tab:: examples/cpp/energy-link/s4u-energy-link.cpp
1080 WiFi network energy consumption
1081 -------------------------------
1083 This example shows how to retrieve and display the energy consumed by the wireless network during communications.
1087 .. example-tab:: examples/cpp/energy-wifi/s4u-energy-wifi.cpp
1089 Modeling the shutdown and boot of hosts
1090 ---------------------------------------
1092 Simple example of a model for the energy consumption during the host boot and shutdown periods.
1096 .. example-tab:: examples/platforms/energy_boot.xml
1098 .. example-tab:: examples/cpp/energy-boot/s4u-energy-boot.cpp
1100 ***********************
1101 Tracing and Visualizing
1102 ***********************
1104 Tracing can be activated by various configuration options which are illustrated in these examples. See also the
1105 :ref:`full list of options related to tracing <tracing_tracing_options>`.
1106 The following introduces some option sets of interest that you may want to pass to your simulators.
1109 These tracing examples should be integrated in the examples to not duplicate the C++ files.
1110 A full command line to see the result in the right tool (vite/FrameSoc) should be given along with some screenshots.
1118 This program is a toy example just loading the platform so that you can play with the platform visualization. Recommended options:
1119 ``--cfg=tracing:yes --cfg=tracing/categorized:yes``
1123 .. example-tab:: examples/cpp/trace-platform/s4u-trace-platform.cpp
1128 This example declares several tracing categories that are used to
1129 classify its tasks. When the program is executed, the tracing mechanism
1130 registers the resource utilization of hosts and links according to these
1131 categories. Recommended options:
1132 ``--cfg=tracing:yes --cfg=tracing/categorized:yes --cfg=tracing/uncategorized:yes``
1136 .. example-tab:: examples/cpp/trace-categories/s4u-trace-categories.cpp
1138 Master Workers tracing
1139 ----------------------
1141 This is an augmented version of our basic master/worker example using
1142 several tracing features. It traces resource usage, sorted out in several
1143 categories; Trace marks and user variables are also used. Recommended
1144 options: ``--cfg=tracing/categorized:yes --cfg=tracing/uncategorized:yes``
1148 .. example-tab:: examples/cpp/trace-masterworkers/s4u-trace-masterworkers.cpp
1150 .. example-tab:: examples/python/app-masterworkers/app-masterworkers.py
1152 Process migration tracing
1153 -------------------------
1155 This version is enhanced so that the process migrations can be displayed
1156 as arrows in a Gantt-chart visualization. Recommended options to that
1157 extend: ``--cfg=tracing:yes --cfg=tracing/actor:yes``
1161 .. example-tab:: examples/cpp/trace-process-migration/s4u-trace-process-migration.cpp
1163 Tracing user variables
1164 ======================
1166 You can also attach your own variables to any resource described in the platform
1167 file. The following examples illustrate this feature. They have to be run with
1168 the following options: ``--cfg=tracing:yes --cfg=tracing/platform:yes``
1170 Attaching variables to Hosts
1171 ----------------------------
1175 .. example-tab:: examples/cpp/trace-host-user-variables/s4u-trace-host-user-variables.cpp
1177 Attaching variables to Links
1178 ----------------------------
1180 The tricky part is that you have to know the name of the link you want to enhance with a variable.
1184 .. example-tab:: examples/cpp/trace-link-user-variables/s4u-trace-link-user-variables.cpp
1186 Attaching variables to network routes
1187 -------------------------------------
1189 It is often easier to update a given variable for all links of a given network path (identified by its source and destination hosts) instead of
1190 knowing the name of each specific link.
1194 .. example-tab:: examples/cpp/trace-route-user-variables/s4u-trace-route-user-variables.cpp
1196 ************************
1197 Larger SimGrid Exemplars
1198 ************************
1200 This section contains application examples that are somewhat larger than the previous examples.
1208 Shows how to implement a classical communication pattern, where a token is exchanged along a ring to reach every participant.
1212 .. example-tab:: examples/cpp/app-token-ring/s4u-app-token-ring.cpp
1214 .. example-tab:: examples/c/app-token-ring/app-token-ring.c
1219 Another good old example, where one Master actor has a bunch of tasks to dispatch to a set of several Worker actors.
1220 This example is used in the :ref:`SimGrid tutorial <usecase_simalgo>`.
1226 This example comes in two equivalent variants, one where the actors
1227 are specified as simple functions (which is easier to understand for
1228 newcomers) and one where the actors are specified as classes (which is
1229 more powerful for the users wanting to build their own projects upon
1232 .. showfile:: examples/cpp/app-masterworkers/s4u-app-masterworkers-class.cpp
1235 .. showfile:: examples/cpp/app-masterworkers/s4u-app-masterworkers-fun.cpp
1240 .. showfile:: examples/c/app-masterworker/app-masterworker.c
1243 .. example-tab:: examples/python/app-masterworkers/app-masterworkers.py
1251 Classical protocol for Peer-to-Peer data diffusion.
1257 .. showfile:: examples/cpp/app-bittorrent/s4u-bittorrent.cpp
1260 .. showfile:: examples/cpp/app-bittorrent/s4u-peer.cpp
1263 .. showfile:: examples/cpp/app-bittorrent/s4u-tracker.cpp
1268 .. showfile:: examples/c/app-bittorrent/app-bittorrent.c
1271 .. showfile:: examples/c/app-bittorrent/bittorrent-peer.c
1274 .. showfile:: examples/c/app-bittorrent/tracker.c
1280 Data broadcast over a ring of processes.
1284 .. example-tab:: examples/cpp/app-chainsend/s4u-app-chainsend.cpp
1288 .. showfile:: examples/c/app-chainsend/chainsend.c
1291 .. showfile:: examples/c/app-chainsend/broadcaster.c
1294 .. showfile:: examples/c/app-chainsend/peer.c
1297 Distributed Hash Tables (DHT)
1298 =============================
1303 One of the most famous DHT protocol.
1309 .. showfile:: examples/cpp/dht-chord/s4u-dht-chord.cpp
1312 .. showfile:: examples/cpp/dht-chord/s4u-dht-chord-node.cpp
1318 Another well-known DHT protocol.
1324 .. showfile:: examples/cpp/dht-kademlia/s4u-dht-kademlia.cpp
1327 .. showfile:: examples/cpp/dht-kademlia/routing_table.cpp
1330 .. showfile:: examples/cpp/dht-kademlia/answer.cpp
1333 .. showfile:: examples/cpp/dht-kademlia/node.cpp
1338 .. showfile:: examples/c/dht-kademlia/dht-kademlia.c
1341 .. showfile:: examples/c/dht-kademlia/routing_table.c
1344 .. showfile:: examples/c/dht-kademlia/answer.c
1347 .. showfile:: examples/c/dht-kademlia/message.c
1350 .. showfile:: examples/c/dht-kademlia/node.c
1356 Yet another well-known DHT protocol.
1360 .. example-tab:: examples/c/dht-pastry/dht-pastry.c
1370 This example starts some computations both on PMs and VMs and migrates some VMs around.
1374 .. example-tab:: examples/cpp/cloud-simple/s4u-cloud-simple.cpp
1376 .. example-tab:: examples/c/cloud-simple/cloud-simple.c
1381 This example shows how to migrate VMs between PMs.
1385 .. example-tab:: examples/cpp/cloud-migration/s4u-cloud-migration.cpp
1387 .. example-tab:: examples/c/cloud-migration/cloud-migration.c
1389 ***********************
1390 Model-Related Examples
1391 ***********************
1396 This simple ping-pong example demonstrates how to use the bindings to the Network
1397 Simulator. The most interesting is probably not the C++ files since
1398 they are unchanged from the other simulations, but the associated files,
1399 such as the platform file to see how to declare a platform to be used
1400 with the ns-3 bindings of SimGrid and the tesh file to see how to
1401 start a simulation in these settings.
1405 .. example-tab:: examples/cpp/network-ns3/s4u-network-ns3.cpp
1411 .. showfile:: examples/platforms/small_platform_one_link_routes.xml
1417 This demonstrates how to declare a wifi zone in your platform and
1418 how to use it in your simulation. For that, you should have a link
1419 whose sharing policy is set to `WIFI`. Such links can have more
1420 than one bandwidth value (separated by commas), corresponding to
1421 the several SNR level of your wifi link.
1423 In this case, SimGrid automatically switches to validated
1424 performance models of wifi networks, where the time is shared
1425 between users instead of the bandwidth for wired links (the
1426 corresponding publication is currently being written).
1428 If your wifi link provides more than one SNR level, you can switch
1429 the level of a given host using
1430 :cpp:func:`simgrid::s4u::Link::set_host_wifi_rate`. By default,
1431 the first level is used.
1435 .. example-tab:: examples/cpp/network-wifi/s4u-network-wifi.cpp
1441 .. showfile:: examples/platforms/wifi.xml
1444 You can also use the **ns-3 models on your wifi networks** as follows:
1448 .. example-tab:: examples/cpp/network-ns3-wifi/s4u-network-ns3-wifi.cpp
1454 .. showfile:: examples/platforms/wifi_ns3.xml
1462 It is possible to extend SimGrid without modifying its internals by
1463 attaching code to the existing signals and by adding extra data to the
1464 simulation objects through extensions. How to do that is not exactly
1465 documented yet, and you should look for examples in the src/plugins
1468 This section documents how the existing plugins can be used. Remember
1469 that you are very welcome to modify the plugins to fit your needs. It
1470 should be much easier than modifying the SimGrid kernel.
1472 Monitoring the host load
1473 ========================
1477 .. example-tab:: examples/cpp/plugin-host-load/s4u-plugin-host-load.cpp
1479 .. example-tab:: examples/c/plugin-host-load/plugin-host-load.c
1481 Monitoring the link load
1482 ========================
1486 .. example-tab:: examples/cpp/plugin-link-load/s4u-plugin-link-load.cpp
1488 ***********************
1489 Model-Checking Examples
1490 ***********************
1492 The model-checker can be used to exhaustively search for issues in the tested application. It must be activated at compile-time, but this
1493 mode is rather experimental in SimGrid (as of v3.25). We are working on it :)
1498 In this example, two actors send some data to a central server, which asserts that the messages are always received in the same order.
1499 This is wrong, and the model-checker correctly finds a counter-example to that assertion.
1503 .. example-tab:: examples/cpp/mc-failing-assert/s4u-mc-failing-assert.cpp