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

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

/** 
 @defgroup MSG_examples MSG examples
 @ingroup MSG_API
 @brief Find the MSG example fitting your needs from the extensive set provided in the archive.

  - @ref msg_ex_basic
  - @ref msg_ex_async
  - @ref msg_ex_process
  - @ref msg_ex_tracing
    - @ref msg_ex_tracing_user_variables
  - @ref msg_ex_models
    - @ref msg_ex_ns3
    - @ref msg_ex_io
  - @ref msg_ex_actions
  - @ref msg_ex_apps
  - @ref msg_ex_misc
                    
@section msg_ex_basic Basic examples and features

 - <b>Ping Pong</b>: @ref examples/msg/app-pingpong/app-pingpong.c\n
   It's hard to think of a simpler example: it is just sending one
   message back and forth.  
   The tesh file laying in the directory show how to start the
   simulator binary, enlighting how to pass options to the simulators
   (as detailed in Section \ref options). 

 - <b>Token Ring</b>.
   @ref examples/msg/app-token-ring/app-token-ring.c\n
   Classical communication pattern, where a token is exchanged
   along a ring to reach every participant. 
   The tesh file laying in the directory shows how to run the same
   example on different virtual platforms.

 - <b>Master Workers</b>.
   @ref examples/msg/app-masterworker/app-masterworker.c\n
   Another good old example, where one Master process has a bunch of
   task to dispatch to a set of several Worker processes. It is fully
   commented in @ref MSG_ex_master_worker.

@section msg_ex_async Asynchronous communications

In addition to the fully documented example of @ref
MSG_ex_asynchronous_communications, there are several other examples
shipped in the archive:
  
 - <b>Basic asynchronous communications</b>. 
   @ref examples/msg/async-wait/async-wait.c \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 MSG_task_isend, @ref MSG_task_irecv, and @ref
   MSG_comm_wait.
 
 - <b>Waiting for all communications in a set</b>.
   @ref examples/msg/async-waitall/async-waitall.c\n
   The @ref MSG_comm_waitall 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/msg/async-waitall/async-waitany.c\n
   The @ref MSG_comm_waitany function is useful when you want to block
   until one activity of the set completes, no matter which terminates
   first.

@section msg_ex_process Acting on Processes

  - <b>Creating processes</b>. 
    @ref examples/msg/process-create/process-create.c \n
    Most processes are started from the deployment XML file, but they
    can also be used with the @ref MSG_process_create() function.

  - <b>Suspend and Resume processes</b>.
    @ref examples/msg/process-suspend/process-suspend.c \n
    Processes can be suspended and resumed during their executions
    thanks to the @ref MSG_process_suspend and @ref MSG_process_resume functions.

  - <b>Kill processes</b>.
    @ref examples/msg/process-kill/process-kill.c \n
    Processes can forcefully stop other processes with the @ref MSG_process_kill function.
     
  - <b>Migrating processes</b>.
    @ref examples/msg/process-migration/process-migration.c \n
    Processes can move or be moved from a host to another with the @ref MSG_process_migrate function.
    
  - <b>Controling the process life cycle from the XML</b>.
    @ref examples/msg/process-startkilltime/process-startkilltime.c \n
    You can specify a start time and a kill time in the deployment
    file. See all *_d.xml files in this directory.

@section msg_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/msg/trace-platform/trace-platform.c \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

  - <b>Setting Categories</b>.
    @ref examples/msg/trace-categories/trace-categories.c \n
    This example declares several tracing categories
    to that are used to classify its tasks. When the program is executed,
    the tracing mechanism registers the resource utilization of hosts
    and links according to these categories. Recommanded options:
    @verbatim --cfg=tracing:yes --cfg=tracing/categorized:yes --cfg=tracing/uncategorized:yes --cfg=viva/categorized:viva_cat.plist --cfg=viva/uncategorized:viva_uncat.plist
    @endverbatim
    
  - <b>Master Workers tracing</b>.
    @ref examples/msg/trace-masterworker/trace-masterworker.c \n
    This is an augmented version of our basic master/worker example
    using several tracing features. It traces resource usage, sorted
    out in several categories; Trace marks and user variables are also
    used. Recommanded options:
    @verbatim --cfg=tracing/categorized:yes --cfg=tracing/uncategorized:yes --cfg=viva/categorized:viva_cat.plist --cfg=viva/uncategorized:viva_uncat.plist
    @endverbatim
    
  - <b>Process migration tracing</b>.
    @ref examples/msg/trace-process-migration/trace-process-migration.c \n
    This version is enhanced so that the process migrations can be
    displayed as arrows in a Gantt-chart visualization. Recommanded
    options to that extend:
    @verbatim -cfg=tracing:yes --cfg=tracing/msg/process:yes
    @endverbatim     

TODO: These tracing examples should be integrated in the examples to
not duplicate the C files. A full command line to see the result in
the right tool (viva/vite/FrameSoc) should be given along with some
screenshots.

@subsection msg_ex_tracing_user_variables Tracing user variables

You can also attach your own variables to a any resource described in
the platform file. The following examples illustrate this feature.
They have to be run with the following options:
@verbatim --cfg=tracing:yes --cfg=tracing/platform:yes
@endverbatim

  - <b>Attaching variables to Hosts</b>.
    @ref examples/msg/trace-host-user-variables/trace-host-user-variables.c 

  - <b>Attaching variables to Links</b>.
    @ref examples/msg/trace-link-user-variables/trace-link-user-variables.c \n
    The tricky part is that you have to know the name of the link you
    want to enhance with a variable.

  - <b>Attaching variables to network Routes</b>
    @ref examples/msg/trace-route-user-variables/trace-route-user-variables.c \n
    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 knowing the name of each specific link.

@section msg_ex_models Models-related examples

@subsection msg_ex_ns3 NS3 as a SimGrid Network Model

This example demonstrates how to use the bindings to the Network
Simulator, as explained in @ref pls. The most
interesting is probably not the C files since they are unchanged from
the other simulations, but the associated files, such as the platform
file to see how to declare a platform to be used with the PLS bindings
of SimGrid and the tesh file to see how to actually start a simulation
in these settings.
  
  - @ref examples/msg/network-ns3/network-ns3.c. Simple ping-pong using
    ns-3 instead of the SimGrid network models.

TODO: merge the C files

TODO: show the XML files instead if it's what is interesting. On a "XML example files" page that does not exist yet.

@subsection msg_ex_io Simulating disks and files

The examples of this section demonstrate how to interact with the
simulated storages.

  - <b>Basic example</b>.
    @ref examples/msg/io-storage/io-storage.c \n
    All main storage and file functions are demoed.
    
  - <b>File Management</b>. @ref examples/msg/io-file/io-file.c \n
    This example illustrates the use of operations on file
    (@ref MSG_file_open, @ref MSG_file_read, @ref MSG_file_write,
    or @ref MSG_file_close).
    
  - <b>Remote I/O</b>. @ref examples/msg/io-remote/io-remote.c \n
    I/O operations can also be done in a remote, i.e. when the
    accessed disk is not mounted on the caller's host.

@section msg_ex_actions Following Workload Traces

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 use @ref MSG_action_trace_run to launch 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/msg/actions-comm/actions-comm.c \n
    Presents a set of event handlers reproducing classical communication
    primitives (synchronous and asynchronous send/receive, broadcast,
    barrier, etc).

  - <b>I/O replay</b>.
    @ref examples/msg/actions-storage/actions-storage.c \n
    Presents a set of event handlers reproducing classical I/O
    primitives (open, read, write, close, etc).

@section msg_ex_apps Examples of Full Applications
 
  - <b>Parallel Matrix Multiplication</b>.
    @ref examples/msg/app-pmm/app-pmm.c \n
    This little application multiplies two matrices in parallel. Each
    of the 9 processes computes a sub-block of the result, with the
    sub-blocks of the input matrices exchanged between the processes. \n
    This is a classical assignment in MPI lectures, here implemented
    in MSG.

  - <b>Chord P2P protocol</b>.
    @ref examples/msg/dht-chord/dht-chord.c \n
    This example implements the well known Chord protocol,
    constituting a fully working non-trivial example. This 
    implementation is also very efficient, as demonstrated in 
    http://hal.inria.fr/inria-00602216/

@section msg_ex_misc Miscellaneous

 - <b>Task priorities</b>.
   @ref examples/msg/task-priority/task-priority.c \n
   Demonstrates the use of @ref MSG_task_set_priority to change the
   computation priority of  a given task.

 - <b>User-defined properties</b>.
   @ref examples/msg/platform-properties/platform-properties.c \n
   Attaching arbitrary information to host, processes and
   such, and retrieving them with @ref MSG_host_get_properties,
   @ref MSG_host_get_property_value, @ref MSG_process_get_properties, and 
   @ref MSG_process_get_property_value. Also make sure to read the
   platform and deployment XML files to see how to declare these data.
 
TODO: Document the many other examples that we have 
*/

As a human, you can stop reading at this point. The rest is garbage:

Every example must be listed in the following, but it's not possible
to move this content upper as each @example directive seems to eat
everything until the next */ marker (and the content is placed at the
top of the example file). 


/**
@defgroup MSG_ex_examples ignored
@example examples/msg/app-pingpong/app-pingpong.c        
@example examples/msg/app-token-ring/app-token-ring.c    
@example examples/msg/app-masterworker/app-masterworker.c

@example examples/msg/async-wait/async-wait.c
@example examples/msg/async-waitall/async-waitall.c
@example examples/msg/async-waitall/async-waitany.c

@example examples/msg/process-create/process-create.c
@example examples/msg/process-suspend/process-suspend.c
@example examples/msg/process-kill/process-kill.c
@example examples/msg/process-migration/process-migration.c
@example examples/msg/process-startkilltime/process-startkilltime.c

@example examples/msg/trace-platform/trace-platform.c
@example examples/msg/trace-categories/trace-categories.c
@example examples/msg/trace-masterworker/trace-masterworker.c
@example examples/msg/trace-process-migration/trace-process-migration.c
@example examples/msg/trace-host-user-variables/trace-host-user-variables.c
@example examples/msg/trace-link-user-variables/trace-link-user-variables.c
@example examples/msg/trace-route-user-variables/trace-route-user-variables.c

@example examples/msg/network-ns3/network-ns3.c

@example examples/msg/io-storage/io-storage.c
@example examples/msg/io-file/io-file.c
@example examples/msg/io-remote/io-remote.c

@example examples/msg/actions-comm/actions-comm.c
@example examples/msg/actions-storage/actions-storage.c

@example examples/msg/app-pmm/app-pmm.c
@example examples/msg/dht-chord/dht-chord.c

@example examples/msg/task-priority/task-priority.c
@example examples/msg/platform-properties/platform-properties.c
                         
*/