docs/source/application.rst

   1 .. _application:
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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.
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  27
  28 .. _S4U_doc:
  29
  30 The S4U Interface
  31 =================
  32
  33 The S4U interface (SimGrid for you) mixes the full power of SimGrid
  34 with the full power of C++. This is the prefered interface to describe
  35 abstract algorithms in the domains of Cloud, P2P, HPC, IoT and similar
  36 settings.
  37
  38 Main Concepts
  39 -------------
  40
  41 A typical SimGrid simulation is composed of several |Actors|_, that
  42 execute user-provided functions. The actors have to explicitly use the
  43 S4U interface to express their
  44 :ref:`computation <exhale_class_classsimgrid_1_1s4u_1_1Exec>`,
  45 :ref:`communication <exhale_class_classsimgrid_1_1s4u_1_1Comm>`,
  46 :ref:`disk usage <exhale_class_classsimgrid_1_1s4u_1_1Io>`,
  47 and other |Activities|_, so that they get reflected within the
  48 simulator. These activities take place on resources such as |Hosts|_,
  49 |Links|_ and |Storages|_. SimGrid predicts the time taken by each
  50 activity and orchestrates accordingly the actors waiting for the
  51 completion of these activities.
  52
  53
  54 When **communicating**, data is not directly sent to other actors but
  55 posted onto a |Mailbox|_ that serve as rendez-vous point between
  56 communicating actors. This means that you don't need to know who you
  57 are talking to, you just put your communication `Send` request in a
  58 mailbox, and it will be matched with a complementary `Receive`
  59 request.  Alternatively, actors can interact through **classical
  60 synchronization mechanisms** such as |Barrier|_, |Semaphore|_,
  61 |Mutex|_ and |ConditionVariable|_.
  62
  63 Each actor is located on a simulated |Host|_. Each host is located
  64 itself in a |NetZone|_, that knows the networking path between one
  65 resource to another. Each NetZone is included in another one, forming
  66 a tree of NetZones which root zone contains the whole platform.
  67
  68 The :ref:`simgrid::s4u::this_actor
  69 <namespace_simgrid__s4u__this_actor>` namespace provides many helper
  70 functions to simplify the code of actors.
  71
  72 - **Global Classes**
  73
  74   - :ref:`class s4u::Actor <exhale_class_classsimgrid_1_1s4u_1_1Actor>`:
  75     Active entities executing your application.
  76   - :ref:`class s4u::Engine <exhale_class_classsimgrid_1_1s4u_1_1Engine>`
  77     Simulation engine (singleton).
  78   - :ref:`class s4u::Mailbox <exhale_class_classsimgrid_1_1s4u_1_1Mailbox>`
  79     Communication rendez-vous.
  80
  81 - **Platform Elements**
  82
  83   - :ref:`class s4u::Host <exhale_class_classsimgrid_1_1s4u_1_1Host>`:
  84     Actor location, providing computational power.
  85   - :ref:`class s4u::Link <exhale_class_classsimgrid_1_1s4u_1_1Link>`
  86     Interconnecting hosts.
  87   - :ref:`class s4u::NetZone <exhale_class_classsimgrid_1_1s4u_1_1NetZone>`:
  88     Sub-region of the platform, containing resources (Hosts, Link, etc).
  89   - :ref:`class s4u::Storage <exhale_class_classsimgrid_1_1s4u_1_1Storage>`
  90     Resource on which actors can write and read data.
  91   - :ref:`class s4u::VirtualMachine <exhale_class_classsimgrid_1_1s4u_1_1VirtualMachine>`:
  92     Execution containers that can be moved between Hosts.
  93
  94 - **Activities** (:ref:`class s4u::Activity <exhale_class_classsimgrid_1_1s4u_1_1Activity>`):
  95   The things that actors can do on resources
  96
  97   - :ref:`class s4u::Comm <exhale_class_classsimgrid_1_1s4u_1_1Comm>`
  98     Communication activity, started on Mailboxes and consuming links.
  99   - :ref:`class s4u::Exec <exhale_class_classsimgrid_1_1s4u_1_1Exec>`
 100     Computation activity, started on Host and consuming CPU resources.
 101   - :ref:`class s4u::Io <exhale_class_classsimgrid_1_1s4u_1_1Io>`
 102     I/O activity, started on and consumming Storages.
 103
 104 - **Synchronization Mechanisms**: Classical IPC that actors can use
 105
 106   - :ref:`class s4u::Barrier <exhale_class_classsimgrid_1_1s4u_1_1Barrier>`
 107   - :ref:`class s4u::ConditionVariable <exhale_class_classsimgrid_1_1s4u_1_1ConditionVariable>`
 108   - :ref:`class s4u::Mutex <exhale_class_classsimgrid_1_1s4u_1_1Mutex>`
 109   - :ref:`class s4u::Semaphore <exhale_class_classsimgrid_1_1s4u_1_1Semaphore>`
 110
 111
 112 .. |Actors| replace:: **Actors**
 113 .. _Actors: api/classsimgrid_1_1s4u_1_1Actor.html
 114
 115 .. |Activities| replace:: **Activities**
 116 .. _Activities: api/classsimgrid_1_1s4u_1_1Activity.html
 117
 118 .. |Hosts| replace:: **Hosts**
 119 .. _Hosts: api/classsimgrid_1_1s4u_1_1Host.html
 120
 121 .. |Links| replace:: **Links**
 122 .. _Links: api/classsimgrid_1_1s4u_1_1Link.html
 123
 124 .. |Storages| replace:: **Storages**
 125 .. _Storages: api/classsimgrid_1_1s4u_1_1Storage.html
 126
 127 .. |VirtualMachines| replace:: **VirtualMachines**
 128 .. _VirtualMachines: api/classsimgrid_1_1s4u_1_1VirtualMachine.html
 129
 130 .. |Host| replace:: **Host**
 131 .. _Host: api/classsimgrid_1_1s4u_1_1Host.html
 132
 133 .. |Mailbox| replace:: **Mailbox**
 134 .. _Mailbox: api/classsimgrid_1_1s4u_1_1Mailbox.html
 135
 136 .. |NetZone| replace:: **NetZone**
 137 .. _NetZone: api/classsimgrid_1_1s4u_1_1NetZone.html
 138
 139 .. |Barrier| replace:: **Barrier**
 140 .. _Barrier: api/classsimgrid_1_1s4u_1_1Barrier.html
 141
 142 .. |ConditionVariable| replace:: **ConditionVariable**
 143 .. _ConditionVariable: api/classsimgrid_1_1s4u_1_1ConditionVariable.html
 144
 145 .. |Mutex| replace:: **Mutex**
 146 .. _Mutex: api/classsimgrid_1_1s4u_1_1Mutex.html
 147
 148
 149 .. include:: app_smpi.rst
 150
 151 .. include:: app_legacy.rst