@tableofcontents
-In order to run any simulation, SimGrid must be provided with three things:
-something to run (i.e., your code), a description of the platform on which you want to simulate your application, and
-information about the deployment of the application: Which process should be executed onto which processor/core?
-
-For the last two items, there are essentially three possible ways you can provide
-this information as an input:
-\li You can program, if you're using MSG, some of the platform and
- deployment functions. If you choose to follow this approach, check the dedicated documentation
- (\ref msg_simulation).
-\li You can use two XML files: one for the platform description and the other for the deployment.
-\li You can program the description of your platform in Lua format.
-
-For more information on SimGrid's deployment features, please refer to the \ref deployment section.
-
-The platform description may be intricate. This documentation is all
-about how to write this file. You should read about the
-@ref routing_basics "routing basic concepts" before proceeding. This page
-first contain a reference guide of the XML. Finally, it gives some hints and tips on how to write a better
-platform description.
-
-\section pf_overview Some words about XML and DTD
-
-We opted for XML not only because it is extensible but also because many tools (and plugins for existing tools) are
-available that facilitate editing and validating XML files. Furthermore, libraries that parse XML are often already
-available and very well tested.
-
-The XML checking is done based on the [simgrid.dtd](http://simgrid.gforge.inria.fr/simgrid/simgrid.dtd) Document Type
-Definition (DTD) file.
-
-If you read the DTD, you should notice the following:
-\li The platform tag has a version attribute. The current version is <b>4</b>. This attribute might be used in the
- provide backward compatibility.
-\li The DTD contains definitions for both the platform description and deployment files used by SimGrid.
-
-\section pf_netzones Defining a netzone
-
-Here is a simplistic example, describing a netzone using the Full
-routing. Other supported values for the routing attribute can be
-found below, Section \ref pf_raf.
-
-
-\verbatim
-<AS id="netzone0" routing="Full">
-\endverbatim
-
-There is also the ``<route>`` tag; this tag takes two attributes,
-``src`` (source) and ``dst`` (destination). Both source and
-destination must be valid identifiers for routers (these will be
-introduced later). Contained by the ``<route>`` are network links;
-these links must be used in order to communicate from the source to
-the destination specified in the tag. Hence, a route merely describes
-how to reach a router from another router.
-
-\remark
- More information and (code-)examples can be found in Section \ref pf_rm.
-
-A netzone can also contain itself one or more netzone; this allows you to model
-the hierarchy of your platform.
-
-### Within each AS, the following types of resources exist:
-
-%Resource | Documented in Section | Description
---------------- | --------------------- | -----------
-AS | | Every Autonomous System (AS) may contain one or more AS.
-host | \ref pf_host | This entity carries out the actual computation. For this reason, it contains processors (with potentially multiple cores).
-router | \ref pf_router | In SimGrid, routers are used to provide helpful information to routing algorithms. Routers may also act as gateways, connecting several autonomous systems with each other.
-link | \ref pf_link | In SimGrid, (network)links define a connection between two or potentially even more resources. Every link has a bandwidth and a latency and may potentially experience congestion.
-cluster | \ref pf_cluster | In SimGrid, clusters were introduced to model large and homogenous environments. They are not really a resource by themselves - technically, they are only a shortcut, as they will internally set up all the hosts, network and routing for you, i.e., using this resource, one can easily setup thousands of hosts and links in a few lines of code. Each cluster is itself an AS.
-
-As it is desirable to interconnect these resources, a routing has to
-be defined. The AS is supposed to be Autonomous, hence this has to be
-done at the AS level. The AS handles two different types of entities
-(<b>host/router</b> and <b>AS</b>). However, the user is responsible
-to define routes between those resources, otherwise entities will be
-unconnected and therefore unreachable from other entities. Although
-several routing algorithms are built into SimGrid (see \ref pf_rm),
-you might encounter a case where you want to define routes manually
-(for instance, due to specific requirements of your platform).
-
-There are three tags to use:
-\li <b>ASroute</b>: to define routes between two <b>AS</b>
-\li <b>route</b>: to define routes between two <b>host/router</b>
-\li <b>bypassRoute</b>: to define routes between two <b>AS</b> that
- will bypass default routing (as specified by the ``routing`` attribute
- supplied to ``<AS>``, see above).
+As @ref starting_components "explained in the introduction," any
+SimGrid study must entail the description of the platform on which you
+want to simulate your application. You have to describe **each element
+of your platform**, such as computing hosts, clusters, each disks,
+links, etc. You must also define the **routing on your platform**, ie
+which path is taken between two hosts. Finally, you may also describe
+an **experimental scenario**, with qualitative changes (e.g.,
+bandwidth changes representing an external load) and qualitative
+changes (representing how some elements fail and restart over time).
+
+You should really separate your application from the platform
+description, as it will ease your experimental campain afterward.
+Mixing them is seen as a really bad experimental practice. The easiest
+to enforce this split is to put the platform description in a XML
+file. Many example platforms are provided in the archive, and this
+page gives all needed details to write such files, as well as some
+hints and tricks about describing your platform.
+
+On the other side, XML is sometimes not expressive enough for some
+platforms, in particular large platforms exhibiting repetitive
+patterns that are not simply expressed in XML. In practice, many
+users end up generating their XML platform files from some sort of
+scripts. It is probably preferable to rewrite your XML @ref
+platform_lua "platform using the lua scripting language" instead.
+In the future, it should be possible to describe the platform directly
+in C++, but this is not possible yet.
+
+As usual, SimGrid is a versatile framework, and you should find the
+way of describing your platform that best fits your experimental
+practice.
+
+\section pf_overview Describing the platform with XML
+
+Your platform description should follow the specification presented in
+the [simgrid.dtd](http://simgrid.gforge.inria.fr/simgrid/simgrid.dtd)
+DTD file. The same DTD is used for both the platform and deployment
+files.
+
+From time to time, this DTD evolves to introduce possibly
+backward-incompatible changes. That is why each platform desciption is
+enclosed within a @c platform tag, that have a @c version attribute.
+The current version is <b>4.1</b>. The @c simgrid_update_xml program can
+upgrade most of the past platform files to the recent formalism.
+
+\section pf_first_example First Platform Example
+
+Here is a very simple platform file, containing 3 resources (two hosts
+and one link), and explicitly giving the route between the hosts.
+
+\code{.xml}
+<?xml version='1.0'?>
+<!DOCTYPE platform SYSTEM "http://simgrid.gforge.inria.fr/simgrid/simgrid.dtd">
+<platform version="4.1">
+ <zone id="first zone" routing="Full">
+ <!-- the resources -->
+ <host id="host1" speed="1Mf"/>
+ <host id="host2" speed="2Mf"/>
+ <link id="link1" bandwidth="125MBps" latency="100us"/>
+ <!-- the routing: specify how the hosts are interconnected -->
+ <route src="host1" dst="host2">
+ <link_ctn id="link1"/>
+ </route>
+ </zone>
+</platform>
+\endcode
+As we said, the englobing @ref pf_overview "<platform>" tag is
+used to specify the dtd version used for this file.
+
+Then, every resource (specified with @ref pf_tag_host, @ref
+pf_tag_link or others) must be located within a given **networking
+zone**. Each zone is in charge of the routing between its
+resources. It means that when an host wants to communicate with
+another host of the same zone, it is the zone's duty to find the list
+of links that are involved in the communication. Here, since the @ref
+pf_tag_zone tag has **Full** as a **routing attribute**, all routes
+must be explicitely given using the @ref pf_tag_route and @ref
+pf_tag_linkctn tags (this @ref pf_rm "routing model" is both simple
+and inefficient :) It is OK to not specify the route between two
+hosts, as long as the processes located on them never try to
+communicate together.
+
+A zone can contain several zones itself, leading to a hierarchical
+decomposition of the platform. This can be more efficient (as the
+inter-zone routing gets factorized with @ref pf_tag_zoneroute), and
+allows to have more than one routing model in your platform. For
+example, you could have a coordinate-based routing for the WAN parts
+of your platforms, a full routing within each datacenter, and a highly
+optimized routing within each cluster of the datacenter. In this
+case, determining the route between two given hosts gets @ref
+routing_basics "somewhat more complex" but SimGrid still computes
+these routes for you in a time- and space-efficient manner.
Here is an illustration of these concepts:
-
- Circles represent processing units and squares represent network routers. Bold
- lines represent communication links. AS2 models the core of a national
- network interconnecting a small flat cluster (AS4) and a larger
- hierarchical cluster (AS5), a subset of a LAN (AS6), and a set of peers
- scattered around the world (AS7).
+
+
+Circles represent processing units and squares represent network
+routers. Bold lines represent communication links. The zone "AS2"
+models the core of a national network interconnecting a small flat
+cluster (AS4) and a larger hierarchical cluster (AS5), a subset of a
+LAN (AS6), and a set of peers scattered around the world (AS7).
\section pf_pftags Resource description
-\subsection pf_As Platform: The <AS> tag
+\subsection pf_tag_zone <zone>
For historical reasons, the XML files use the expression AS for
NetZones. Netzones are very important because they group other resources (such
\subsection pf_Cr Computing resources: hosts, clusters and peers.
-\subsubsection pf_host <host>
+\subsubsection pf_tag_host <host>
A <b>host</b> represents a computer/node card. Every host is able to execute
code and it can send and receive data to/from other hosts. Most importantly,
radical | yes | string | Regexp used to generate cluster nodes name. Syntax: "10-20" will give you 11 machines numbered from 10 to 20, "10-20;2" will give you 12 machines, one with the number 2, others numbered as before. The produced number is concatenated between prefix and suffix to form machine names.
speed | yes | int | Same as the ``speed`` attribute of the ``\<host\>`` tag.
core | no | int (default: 1) | Same as the ``core`` attribute of the ``\<host\>`` tag.
-bw | yes | int | Bandwidth for the links between nodes and backbone (if any). See the \ref pf_link "link section" for syntax/details.
+bw | yes | int | Bandwidth for the links between nodes and backbone (if any). See the \ref pf_tag_link "link section" for syntax/details.
lat | yes | int | Latency for the links between nodes and backbone (if any). See <b>link</b> section for syntax/details.
sharing_policy | no | string | Sharing policy for the links between nodes and backbone (if any). See <b>link</b> section for syntax/details.
bb_bw | no | int | Bandwidth for backbone (if any). See <b>link</b> section for syntax/details. If bb_bw and bb_lat (see below) attributes are omitted, no backbone is created (alternative cluster architecture <b>described before</b>).
prefix | yes | string | Each node of the cabinet has to have a name. This name will be prefixed with this prefix.
suffix | yes | string | Each node of the cabinet will be suffixed with this suffix
radical | yes | string | Regexp used to generate cabinet nodes name. Syntax: "10-20" will give you 11 machines numbered from 10 to 20, "10-20;2" will give you 12 machines, one with the number 2, others numbered as before. The produced number is concatenated between prefix and suffix to form machine names.
-speed | yes | int | Same as the ``speed`` attribute of the \ref pf_host "<host>" tag.
-bw | yes | int | Bandwidth for the links between nodes and backbone (if any). See the \ref pf_link "link section" for syntax/details.
-lat | yes | int | Latency for the links between nodes and backbone (if any). See the \ref pf_link "link section" for syntax/details.
+speed | yes | int | Same as the ``speed`` attribute of the \ref pf_tag_host "<host>" tag.
+bw | yes | int | Bandwidth for the links between nodes and backbone (if any). See the \ref pf_tag_link "link section" for syntax/details.
+lat | yes | int | Latency for the links between nodes and backbone (if any). See the \ref pf_tag_link "link section" for syntax/details.
\note
Please note that as of now, it is impossible to change attributes such as,
<router id="gw_dc1_horizdist"/>
\endverbatim
-\subsubsection pf_link <link/>
+\subsubsection pf_tag_link <link>
Network links can represent one-hop network connections. They are
characterized by their id and their bandwidth; links can (but may not) be subject
--------------- | -----------
\ref pf_storage_entity_storage_type "storage_type" | Defines a template for a particular kind of storage (such as a hard-drive) and specifies important features of the storage, such as capacity, performance (read/write), contents, ... Different models of hard-drives use different storage_types (because the difference between an SSD and an HDD does matter), as they differ in some specifications (e.g., different sizes or read/write performance).
\ref pf_storage_entity_storage "storage" | Defines an actual instance of a storage type (disk, RAM, ...); uses a ``storage_type`` template (see line above) so that you don't need to re-specify the same details over and over again.
-\ref pf_storage_entity_mount "mount" | Must be wrapped by a \ref pf_host tag; declares which storage(s) this host has mounted and where (i.e., the mountpoint).
+\ref pf_storage_entity_mount "mount" | Must be wrapped by a \ref pf_tag_host tag; declares which storage(s) this host has mounted and where (i.e., the mountpoint).
\anchor pf_storage_content_file
| id | yes | string | Refers to a \ref pf_storage_entity_storage "<storage>" entity that will be mounted on that computer |
| name | yes | string | Path/location to/of the logical reference (mount point) of this disk
-This tag must be enclosed by a \ref pf_host tag. It then specifies where the mountpoint of a given storage device (defined by the ``id`` attribute)
+This tag must be enclosed by a \ref pf_tag_host tag. It then specifies where the mountpoint of a given storage device (defined by the ``id`` attribute)
is; this location is specified by the ``name`` attribute.
Here is a simple example, taken from the file ``examples/platform/storage.xml``:
uses this model, SimGrid will fail unless you have explicitly activated the
\ref options_model_select_network_constant "Constant Network Model" (this model charges
the same for every single communication). It should
-be noted, however, that you can still attach an \ref pf_routing_tag_asroute "ASroute",
+be noted, however, that you can still attach an \ref pf_tag_asroute "ASroute",
as is demonstrated in the example below:
\verbinclude platforms/cluster_and_one_host.xml
| Name | Description |
| ------------------------------------------------- | ----------------------------------------------------------------------------------- |
-| \ref pf_routing_tag_route "route" | Used to define route between host/router |
-| \ref pf_routing_tag_asroute "ASroute" | Used to define route between different AS |
-| \ref pf_routing_tag_bypassroute "bypassRoute" | Used to supersede normal routes as calculated by the network model between host/router; e.g., can be used to use a route that is not the shortest path for any of the shortest-path routing models. |
-| \ref pf_routing_tag_bypassasroute "bypassASroute" | Used in the same way as bypassRoute, but for AS |
+| \ref pf_tag_route "route" | Used to define route between host/router |
+| \ref pf_tag_zoneroute "zoneRoute" | Used to define route between different zones |
+| \ref pf_tag_bypassroute "bypassRoute" | Used to supersede normal routes as calculated by the network model between host/router; e.g., can be used to use a route that is not the shortest path for any of the shortest-path routing models. |
+| \ref pf_tag_bypassasroute "bypassZoneRoute" | Used in the same way as bypassRoute, but for zones |
Basically all those tags will contain an (ordered) list of references
to link that compose the route you want to define.
\endverbatim
The route here from host Alice to Bob will be first link1, then link2,
-and finally link3. What about the reverse route? \ref pf_routing_tag_route "Route" and
-\ref pf_routing_tag_asroute "ASroute" have an optional attribute \c symmetrical, that can
+and finally link3. What about the reverse route? \ref pf_tag_route "Route" and
+\ref pf_tag_zoneroute "ASroute" have an optional attribute \c symmetrical, that can
be either \c YES or \c NO. \c YES means that the reverse route is the same
route in the inverse order, and is set to \c YES by default. Note that
this is not the case for bypass*Route, as it is more probable that you
want to bypass only one default route.
-For an \ref pf_routing_tag_asroute "ASroute", things are just slightly more complicated, as you have
+For an \ref pf_tag_zoneroute "ASroute", things are just slightly more complicated, as you have
to give the id of the gateway which is inside the AS you want to access ...
So it looks like this:
pass through link1, and get into AS2 by being received by router2.
router1 must belong to AS1 and router2 must belong to AS2.
-\subsubsection pf_linkctn <link_ctn/>
+\subsubsection pf_tag_linkctn <link_ctn>
This entity has only one purpose: Refer to an already existing
-\ref pf_link "<link/>" when defining a route, i.e., it
-can only occur as a child of \ref pf_routing_tag_route "<route/>"
+\ref pf_tag_link "<link/>" when defining a route, i.e., it
+can only occur as a child of \ref pf_tag_route "<route/>"
| Attribute name | Mandatory | Values | Description |
| --------------- | --------- | ------ | ----------- |
\verbinclude example_filelist_xmltag_linkctn
-\subsubsection pf_routing_tag_asroute ASroute
+\subsubsection pf_tag_zoneroute <zoneRoute>
The purpose of this entity is to define a route between two ASes.
This is mainly useful when you're in the \ref pf_routing_model_full "Full routing model".
| --------------- | --------- | ------ | ----------- |
| src | yes | String | The identifier of the source AS |
| dst | yes | String | See the \c src attribute |
-| gw_src | yes | String | The gateway that will be used within the src AS; this can be any \ref pf_host "Host" or \ref pf_router "Router" defined within the src AS. |
+| gw_src | yes | String | The gateway that will be used within the src AS; this can be any \ref pf_tag_host "Host" or \ref pf_router "Router" defined within the src AS. |
| gw_dst | yes | String | Same as \c gw_src, but with the dst AS instead. |
| symmetrical | no | YES\|NO (Default: YES) | If this route is symmetric, the opposite route (from dst to src) will also be declared implicitly. |
</AS>
\endverbatim
-\subsubsection pf_routing_tag_route route
+\subsubsection pf_tag_route <route>
The principle is the same as for
-\ref pf_routing_tag_asroute "ASroute": The route contains a list of links that
+\ref pf_tag_zoneroute "ASroute": The route contains a list of links that
provide a path from \c src to \c dst. Here, \c src and \c dst can both be either a
-\ref pf_host "host" or \ref pf_router "router". This is mostly useful for the
+\ref pf_tag_host "host" or \ref pf_router "router". This is mostly useful for the
\ref pf_routing_model_full "Full routing model" as well as for the
\ref pf_routing_model_shortest_path "shortest-paths" based models (as they require
topological information).
(network-)graph and the employed algorithms need to know which edge connects
which pair of entities.
-\subsubsection pf_routing_tag_bypassasroute bypassASroute
+\subsubsection pf_tag_bypassasroute bypassASroute
As said before, once you choose
a model, it (most likely; the constant network model, for example, doesn't) calculates routes for you. But maybe you want to
\c my_cluster_2_router in the destination router. Additionally, as the \c symmetrical
attribute was not given, this route is presumed to be symmetrical.
-\subsubsection pf_routing_tag_bypassroute bypassRoute
+\subsubsection pf_tag_bypassroute bypassRoute
As said before, once you choose
a model, it (most likely; the constant network model, for example, doesn't) calculates routes for you. But maybe you want to
| --------------- | --------- | ---------------------- | ----------- |
| id | yes | String | Identifier of this trace; this is the name you pass on to \c trace_connect. |
| file | no | String | Filename of the file that contains the information - the path must follow the style of your OS. You can omit this, but then you must specifiy the values inside of <trace> and </trace> - see the example below. |
-| trace_periodicity | yes | String | This is the same as for \ref pf_host "hosts" (see there for details) |
+| trace_periodicity | yes | String | This is the same as for \ref pf_tag_host "hosts" (see there for details) |
Here is an example of trace when no file name is provided:
