docs/source/application.rst

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  14
  15 Describing your Application
  16 ***************************
  17
  18 Every SimGrid simulation entails a distributed application, that
  19 virtually executes on the simulated platform. This application can
  20 be either an existing MPI program (if you use the SMPI interface), or
  21 a program specifically written to execute within SimGrid, using one of
  22 the dedicated APIs.
  23
  24 .. _S4U_doc:
  25
  26 The S4U Interface
  27 =================
  28
  29 The S4U interface (SimGrid for you) mixes the full power of SimGrid
  30 with the full power of C++. This is the prefered interface to describe
  31 abstract algorithms in the domains of Cloud, P2P, HPC, IoT and similar
  32 settings.
  33
  34 Main Concepts
  35 -------------
  36
  37 A typical SimGrid simulation is composed of several |Actors|_, that
  38 execute user-provided functions. The actors have to explicitly use the
  39 S4U interface to express their
  40 :ref:`computation <exhale_class_classsimgrid_1_1s4u_1_1Exec>`,
  41 :ref:`communication <exhale_class_classsimgrid_1_1s4u_1_1Comm>`,
  42 :ref:`disk usage <exhale_class_classsimgrid_1_1s4u_1_1Io>`,
  43 and other |Activities|_, so that they get reflected within the
  44 simulator. These activities take place on resources such as |Hosts|_,
  45 |Links|_ and |Storages|_. SimGrid predicts the time taken by each
  46 activity and orchestrates accordingly the actors waiting for the
  47 completion of these activities.
  48
  49
  50 When **communicating**, data is not directly sent to other actors but
  51 posted onto a |Mailbox|_ that serve as rendez-vous point between
  52 communicating actors. This means that you don't need to know who you
  53 are talking to, you just put your communication `Send` request in a
  54 mailbox, and it will be matched with a complementary `Receive`
  55 request.  Alternatively, actors can interact through **classical
  56 synchronization mechanisms** such as |Barrier|_, |Semaphore|_,
  57 |Mutex|_ and |ConditionVariable|_.
  58
  59 Each actor is located on a simulated |Host|_. Each host is located
  60 itself in a |NetZone|_, that route communications through the
  61 links. Each NetZone is included in another one, forming a tree of
  62 NetZones which root zone contains the whole platform.
  63
  64 The :ref:`simgrid::s4u::this_actor
  65 <namespace_simgrid__s4u__this_actor>` namespace provides many helper
  66 functions to simplify the code of actors.
  67
  68 - **Global Classes**
  69
  70   - :ref:`class s4u::Actor <exhale_class_classsimgrid_1_1s4u_1_1Actor>`:
  71     Active entities executing your application.
  72   - :ref:`class s4u::Engine <exhale_class_classsimgrid_1_1s4u_1_1Engine>`
  73     Simulation engine (singleton).
  74   - :ref:`class s4u::Mailbox <exhale_class_classsimgrid_1_1s4u_1_1Mailbox>`
  75     Communication rendez-vous.
  76
  77 - **Platform Elements**
  78
  79   - :ref:`class s4u::Host <exhale_class_classsimgrid_1_1s4u_1_1Host>`:
  80     Actor location, providing computational power.
  81   - :ref:`class s4u::Link <exhale_class_classsimgrid_1_1s4u_1_1Link>`
  82     Interconnecting hosts.
  83   - :ref:`class s4u::NetZone <exhale_class_classsimgrid_1_1s4u_1_1NetZone>`:
  84     Sub-region of the platform, containing resources (Hosts, Link, etc).
  85   - :ref:`class s4u::Storage <exhale_class_classsimgrid_1_1s4u_1_1Storage>`
  86     Resource on which actors can write and read data.
  87   - :ref:`class s4u::VirtualMachine <exhale_class_classsimgrid_1_1s4u_1_1VirtualMachine>`:
  88     Execution containers that can be moved between Hosts.
  89
  90 - **Activities** (:ref:`class s4u::Activity <exhale_class_classsimgrid_1_1s4u_1_1Activity>`):
  91   The things that actors can do on resources
  92
  93   - :ref:`class s4u::Comm <exhale_class_classsimgrid_1_1s4u_1_1Comm>`
  94     Communication activity, started on Mailboxes and consuming links.
  95   - :ref:`class s4u::Exec <exhale_class_classsimgrid_1_1s4u_1_1Exec>`
  96     Computation activity, started on Host and consuming CPU resources.
  97   - :ref:`class s4u::Io <exhale_class_classsimgrid_1_1s4u_1_1Io>`
  98     I/O activities, started on and consumming Storages.
  99
 100 - **Synchronization Mechanisms**: Classical IPC that actors can use
 101
 102   - :ref:`class s4u::Barrier <exhale_class_classsimgrid_1_1s4u_1_1Barrier>`
 103   - :ref:`class s4u::ConditionVariable <exhale_class_classsimgrid_1_1s4u_1_1ConditionVariable>`
 104   - :ref:`class s4u::Mutex <exhale_class_classsimgrid_1_1s4u_1_1Mutex>`
 105   - :ref:`class s4u::Semaphore <exhale_class_classsimgrid_1_1s4u_1_1Semaphore>`
 106
 107
 108 .. |Actors| replace:: **Actors**
 109 .. _Actors: api/classsimgrid_1_1s4u_1_1Actor.html
 110
 111 .. |Activities| replace:: **Activities**
 112 .. _Activities: api/classsimgrid_1_1s4u_1_1Activity.html
 113
 114 .. |Hosts| replace:: **Hosts**
 115 .. _Hosts: api/classsimgrid_1_1s4u_1_1Host.html
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 117 .. |Links| replace:: **Links**
 118 .. _Links: api/classsimgrid_1_1s4u_1_1Link.html
 119
 120 .. |Storages| replace:: **Storages**
 121 .. _Storages: api/classsimgrid_1_1s4u_1_1Storage.html
 122
 123 .. |VirtualMachines| replace:: **VirtualMachines**
 124 .. _VirtualMachines: api/classsimgrid_1_1s4u_1_1VirtualMachine.html
 125
 126 .. |Host| replace:: **Host**
 127 .. _Host: api/classsimgrid_1_1s4u_1_1Host.html
 128
 129 .. |Mailbox| replace:: **Mailbox**
 130 .. _Mailbox: api/classsimgrid_1_1s4u_1_1Mailbox.html
 131
 132 .. |NetZone| replace:: **NetZone**
 133 .. _NetZone: api/classsimgrid_1_1s4u_1_1NetZone.html
 134
 135 .. |Barrier| replace:: **Barrier**
 136 .. _Barrier: api/classsimgrid_1_1s4u_1_1Barrier.html
 137
 138 .. |ConditionVariable| replace:: **ConditionVariable**
 139 .. _ConditionVariable: api/classsimgrid_1_1s4u_1_1ConditionVariable.html
 140
 141 .. |Mutex| replace:: **Mutex**
 142 .. _Mutex: api/classsimgrid_1_1s4u_1_1Mutex.html
 143
 144
 145 .. include:: app_smpi.rst
 146
 147 .. include:: app_legacy.rst