[simgrid.git] / examples / s4u / README.doc

S4U (Simgrid for you) is the next interface of SimGrid, expected to be released with SimGrid 4.0.

Even if it is not completely rock stable yet, it may well already fit
your needs. You are welcome to try it and report any interface
glitches that you see. Be however warned that the interface may change
until the final release.  You will have to adapt your code on the way.

This file follows the Doxygen syntax to be included in the
documentation, but it should remain readable directly.

/** 
 @defgroup s4u_examples S4U examples
 @ingroup s4u_api
 @brief Find the S4U example fitting your needs in the archive.

SimGrid comes with an extensive set of examples, documented on this
page. Most of them only demonstrate one single feature, with some
larger examplars listed below. 

Each of these examples can be found in a subdirectory under
examples/s4u in the archive. It contains the source code (also listed
from this page), and the so-called tesh file containing how to call
the binary obtained by compiling this example and also the expected
output. Tesh files are used to turn each of our examples into an
integration test. Some examples also contain other files, on need.

A good way to bootstrap your own project is to copy and combine some
of the provided examples to constitute the skeleton of what you plan
to simulate.

  - @ref s4u_ex_actors
    - @ref s4u_ex_actors_start
    - @ref s4u_ex_actors_synchro
    - @ref s4u_ex_actors_replay
  - @ref s4u_ex_activities
    - @ref s4u_ex_activity_comm
    - @ref s4u_ex_activity_exec
    - @ref s4u_ex_activity_io
    - @ref s4u_ex_activity_synchro
  - @ref s4u_ex_platf
  - @ref s4u_ex_energy
  - @ref s4u_ex_tracing
  - @ref s4u_ex_app
    - @ref s4u_ex_app_data
    - @ref s4u_ex_app_dht

TODO: document here the examples about plugins
    
@section s4u_ex_actors Actors: the active entities

@subsection s4u_ex_actors_start Starting and stoping actors

  - <b>Creating actors</b>. 
    @ref examples/s4u/actor-create/s4u-actor-create.cpp @n
    Most actors are started from the deployment XML file, but there is other methods.
    This example show them all.

  - <b>Kill actors</b>.
    @ref examples/s4u/actor-kill/s4u-actor-kill.cpp @n
    Actors can forcefully stop other actors with the @ref
    simgrid::s4u::Actor::kill(void) or the @ref
    simgrid::s4u::Actor::kill(aid_t) methods.

  - <b>Controling the actor life cycle from the XML</b>.
    @ref examples/s4u/actor-lifetime/s4u-actor-lifetime.cpp 
    @ref examples/s4u/actor-lifetime/s4u-actor-lifetime_d.xml 
    @n
    You can specify a start time and a kill time in the deployment file.

  - <b>Daemonize actors</b>
    @ref examples/s4u/actor-daemon/s4u-actor-daemon.cpp @n
    Some actors may be intended to simulate daemons that run in background. This example show how to transform a regular
    actor into a daemon that will be automatically killed once the simulation is over. 
    
@subsection s4u_ex_actors_synchro Inter-actors interactions

  - <b>Suspend and Resume actors</b>.
    @ref examples/s4u/actor-suspend/s4u-actor-suspend.cpp @n
    Actors can be suspended and resumed during their executions
    thanks to the @ref simgrid::s4u::Actor::suspend and @ref simgrid::s4u::Actor::resume methods.

  - <b>Migrating Actors</b>.
    @ref examples/s4u/actor-migration/s4u-actor-migration.cpp @n
    Actors can move or be moved from a host to another with the @ref
    simgrid::s4u::this_actor::migrate() method.

  - <b>Waiting for the termination of an actor</b> (joining on it)
    @ref examples/s4u/actor-join/s4u-actor-join.cpp @n
    The simgrid::s4u::Actor::join() method allows to block the current
    actor until the end of the receiving actor.

  - <b>Yielding to other actor</b>.
    @ref examples/s4u/actor-yield/s4u-actor-yield.cpp@n
    The simgrid::s4u::this_actor::yield() function interrupts the
    execution of the current actor, leaving a chance to the other actors
    that are ready to run at this timestamp.

@subsection s4u_ex_actors_replay Traces Replay as a Workload

This section details how to run trace-driven simulations. It is very
handy when you want to test an algorithm or protocol that only react
to external events. For example, many P2P protocols react to user
requests, but do nothing if there is no such event.

In such situations, you should write your protocol in C++, and separate
the workload that you want to play onto your protocol in a separate
text file. Declare a function handling each type of the events in your
trace, register them using @ref xbt_replay_action_register in your
main, and then run the simulation.

Then, you can either have one trace file containing all your events,
or a file per simulated process: the former may be easier to work
with, but the second is more efficient on very large traces. Check
also the tesh files in the example directories for details.

  - <b>Communication replay</b>.
    @ref examples/s4u/replay-comm/s4u-replay-comm.cpp @n
    Presents a set of event handlers reproducing classical communication
    primitives (asynchronous send/receive at the moment).

  - <b>I/O replay</b>.
    @ref examples/s4u/replay-storage/s4u-replay-storage.cpp @n
    Presents a set of event handlers reproducing classical I/O
    primitives (open, read, close).

@section s4u_ex_activities Activities: the things that Actors do

@subsection s4u_ex_activity_comm Communications on the network

 - <b>Basic asynchronous communications</b>. 
   @ref examples/s4u/async-wait/s4u-async-wait.cpp @n
   Illustrates how to have non-blocking communications, that are
   communications running in the background leaving the process free
   to do something else during their completion. The main functions
   involved are @ref simgrid::s4u::Mailbox::put_async and 
   @ref simgrid::s4u::Comm::wait().

 - <b>Waiting for all communications in a set</b>.
   @ref examples/s4u/async-waitall/s4u-async-waitall.cpp@n
   The @ref simgrid::s4u::Comm::wait_all() function is useful when you want to block
   until all activities in a given set have completed.

 - <b>Waiting for the first completed communication in a set</b>.
   @ref examples/s4u/async-waitany/s4u-async-waitany.cpp@n
   The @ref simgrid::s4u::Comm::wait_any() function is useful when you want to block
   until one activity of the set completes, no matter which terminates
   first.    

@subsection s4u_ex_activity_exec Executions on the CPU

  - <b>Basic execution</b>.
    @ref examples/s4u/exec-basic/s4u-exec-basic.cpp @n
    The computations done in your program are not reported to the
    simulated world, unless you explicitely request the simulator to pause
    the actor until a given amount of flops gets computed on its simulated
    host. Some executions can be given an higher priority so that they
    get more resources.

  - <b>Asynchronous execution</b>.
    @ref examples/s4u/exec-async/s4u-exec-async.cpp @n
    You can start asynchronous executions, just like you would fire
    background threads.
    
  - <b>Monitoring asynchronous executions</b>.
    @ref examples/s4u/exec-monitor/s4u-exec-monitor.cpp @n
    This example shows how to start an asynchronous execution, and
    monitor its status.
    
  - <b>Remote execution</b>.
    @ref examples/s4u/exec-remote/s4u-exec-remote.cpp @n
    Before its start, you can change the host on which a given execution will occur.

  - <b>Using Pstates on a host</b>
    @ref examples/s4u/exec-dvfs/s4u-exec-dvfs.cpp and 
    @ref examples/platforms/energy_platform.xml @n
    Show how define a set of pstatesfor a host in the XML, and how the current
    pstate can be accessed/changed with @ref simgrid::s4u::Host::get_pstate_speed and @ref simgrid::s4u::Host::set_pstate.

  - <b>Parallel tasks</b>
    @ref examples/s4u/exec-ptask/s4u-exec-ptask.cpp@n
    These objects are convenient abstractions of parallel
    computational kernels that span over several machines. 

@subsection s4u_ex_activity_io I/O on disks and files

SimGrid provides two levels of abstraction to interact with the
simulated storages. At the simplest level, you simply create read and
write actions on the storage resources.

  - <b>Access to raw storage devices</b>.
    @ref examples/s4u/io-storage-raw/s4u-io-storage-raw.cpp @n
    This example illustrates how to simply read and write data on a
    simulated storage resource.

The FileSystem plugin provides a more detailed view, with the
classical operations over files: open, move, unlink, and of course
read and write. The file and disk sizes are also dealt with and can
result in short reads and short write, as in reality.

  - <b>File Management</b>. @ref examples/s4u/io-file-system/s4u-io-file-system.cpp @n
    This example illustrates the use of operations on files
    (read, write, seek, tell, unlink, ...).

  - <b>Remote I/O</b>. 
    @ref examples/s4u/io-file-remote/s4u-io-file-remote.cpp @n
    I/O operations on files can also be done in a remote fashion, 
    i.e. when the accessed disk is not mounted on the caller's host.

@subsection s4u_ex_activity_synchro Classical synchronization objects

 - <b>Mutex: </b> @ref examples/s4u/mutex/s4u-mutex.cpp @n
   Shows how to use simgrid::s4u::Mutex synchronization objects.

@section s4u_ex_platf Interacting with the platform

 - <b>Retrieving the list of hosts matching a given criteria</b>.
   @ref examples/s4u/engine-filtering/s4u-engine-filtering.cpp@n
   Filtering the actors that match a given criteria is rather simple.

 - <b>User-defined properties</b>.
   @ref examples/s4u/platform-properties/s4u-platform-properties.cpp and 
   @ref examples/s4u/platform-properties/s4u-platform-properties_d.xml and
   @ref examples/platforms/prop.xml @n
   You can attach arbitrary information to most platform elements from
   the XML file, and then interact with these values from your
   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
   your simulation. 
   - simgrid::s4u::Actor::get_property() and simgrid::s4u::Actor::set_property()
   - simgrid::s4u::Host::get_property() and simgrid::s4u::Host::set_property()
   - simgrid::s4u::Link::get_property() and simgrid::s4u::Link::set_property()
   - simgrid::s4u::NetZone::get_property() and simgrid::s4u::NetZone::set_property()

@section s4u_ex_energy Simulating the energy consumption

  - <b>Describing the energy profiles in the platform</b>
    @ref examples/platforms/energy_platform.xml @n
    This platform file contains the energy profile of each links and
    hosts, which is necessary to get energy consumption predictions.
    As usual, you should not trust our example, and you should strive
    to double-check that your instanciation matches your target platform.

  - <b>Consumption due to the CPU</b> 
    @ref examples/s4u/energy-exec/s4u-energy-exec.cpp @n
    This example shows how to retrieve the amount of energy consumed
    by the CPU during computations, and the impact of the pstate.

  - <b>Consumption due to the network</b>
    @ref examples/s4u/energy-link/s4u-energy-link.cpp
    This example shows how to retrieve and display the energy consumed
    by the network during communications.

  - <b>Modeling the shutdown and boot of hosts</b>
    @ref examples/s4u/energy-boot/platform_boot.xml
    @ref examples/s4u/energy-boot/s4u-energy-boot.cpp@n
    Simple example of model of model for the energy consumption during
    the host boot and shutdown periods.

@section s4u_ex_tracing Tracing and visualization features

Tracing can be activated by various configuration options which
are illustrated in these example. See also the 
@ref tracing_tracing_options "full list of options related to tracing".

It is interesting to run the process-create example with the following
options to see the task executions:

  - <b>Platform tracing</b>.
    @ref examples/s4u/trace-platform/s4u-trace-platform.cpp @n
    This program is a toy example just loading the platform, so that
    you can play with the platform visualization. Recommanded options:
    @verbatim --cfg=tracing:yes --cfg=tracing/categorized:yes
    @endverbatim

@section s4u_ex_app Larger SimGrid examplars

This section contains application examples that are somewhat larger
than the previous examples.

  - <b>Ping Pong</b>: @ref examples/s4u/app-pingpong/s4u-app-pingpong.cpp@n
    This simple example just sends one message back and forth.
    The tesh file laying in the directory show how to start the simulator binary, highlighting how to pass options to 
    the simulators (as detailed in Section @ref options). 

  - <b>Token ring:</b> @ref examples/s4u/app-token-ring/s4u-app-token-ring.cpp @n
    Shows how to implement a classical communication pattern, where a token is exchanged along a ring to reach every
    participant.

  - <b>Master Workers:</b> @ref examples/s4u/app-masterworkers/s4u-app-masterworkers-class.cpp 
                           @ref examples/s4u/app-masterworkers/s4u-app-masterworkers-fun.cpp @n
    Another good old example, where one Master process has a bunch of task to dispatch to a set of several Worker 
    processes. This example comes in two equivalent variants, one
    where the actors are specified as simple functions (which is easier to
    understand for newcomers) and one where the actors are specified
    as classes (which is more powerful for the users wanting to build
    their own projects upon the example).
    
@subsection s4u_ex_app_data Data diffusion

  - <b>Bit Torrent</b> 
    @ref examples/s4u/app-bittorrent/s4u-bittorrent.cpp@n
    Classical protocol for Peer-to-Peer data diffusion.
    
  - <b>Chained send</b> 
    @ref examples/s4u/app-chainsend/s4u-app-chainsend.cpp@n
    Data broadcast over a ring of processes.

@subsection s4u_ex_app_dht Distributed Hash Tables (DHT)

  - <b>Chord Protocol</b> 
    @ref examples/s4u/dht-chord/s4u-dht-chord.cpp@n
    One of the most famous DHT protocol.

*/

/**
@example examples/s4u/actor-create/s4u-actor-create.cpp
@example examples/s4u/actor-create/s4u-actor-create_d.xml
@example examples/s4u/actor-daemon/s4u-actor-daemon.cpp
@example examples/s4u/actor-join/s4u-actor-join.cpp
@example examples/s4u/actor-kill/s4u-actor-kill.cpp
@example examples/s4u/actor-lifetime/s4u-actor-lifetime.cpp 
@example examples/s4u/actor-lifetime/s4u-actor-lifetime_d.xml 
@example examples/s4u/actor-migration/s4u-actor-migration.cpp
@example examples/s4u/actor-suspend/s4u-actor-suspend.cpp
@example examples/s4u/actor-yield/s4u-actor-yield.cpp
@example examples/s4u/async-wait/s4u-async-wait.cpp
@example examples/s4u/async-waitall/s4u-async-waitall.cpp
@example examples/s4u/async-waitany/s4u-async-waitany.cpp
@example examples/s4u/app-bittorrent/s4u-bittorrent.cpp
@example examples/s4u/app-chainsend/s4u-app-chainsend.cpp
@example examples/s4u/app-masterworkers/s4u-app-masterworkers-class.cpp
@example examples/s4u/app-masterworkers/s4u-app-masterworkers-fun.cpp
@example examples/s4u/app-pingpong/s4u-app-pingpong.cpp
@example examples/s4u/app-token-ring/s4u-app-token-ring.cpp
@example examples/s4u/dht-chord/s4u-dht-chord.cpp
@example examples/s4u/engine-filtering/s4u-engine-filtering.cpp
@example examples/s4u/energy-boot/platform_boot.xml
@example examples/s4u/energy-boot/s4u-energy-boot.cpp
@example examples/s4u/energy-exec/s4u-energy-exec.cpp
@example examples/s4u/energy-link/s4u-energy-link.cpp
@example examples/s4u/exec-basic/s4u-exec-basic.cpp
@example examples/s4u/exec-async/s4u-exec-async.cpp
@example examples/s4u/exec-dvfs/s4u-exec-dvfs.cpp
@example examples/s4u/exec-monitor/s4u-exec-monitor.cpp
@example examples/s4u/exec-ptask/s4u-exec-ptask.cpp
@example examples/s4u/exec-remote/s4u-exec-remote.cpp 
@example examples/s4u/io-file-system/s4u-io-file-system.cpp
@example examples/s4u/io-file-remote/s4u-io-file-remote.cpp
@example examples/s4u/io-storage-raw/s4u-io-storage-raw.cpp
@example examples/s4u/mutex/s4u-mutex.cpp
@example examples/s4u/platform-properties/s4u-platform-properties.cpp
@example examples/s4u/platform-properties/s4u-platform-properties_d.xml
@example examples/s4u/replay-comm/s4u-replay-comm.cpp
@example examples/s4u/replay-storage/s4u-replay-storage.cpp
@example examples/s4u/trace-platform/s4u-trace-platform.cpp
@example examples/platforms/energy_platform.xml
@example examples/platforms/prop.xml

*/