1 /* Copyright (c) 2004-2023. The SimGrid Team. All rights reserved. */
3 /* This program is free software; you can redistribute it and/or modify it
4 * under the terms of the license (GNU LGPL) which comes with this package. */
9 #include <simgrid/forward.h>
10 #include <simgrid/kernel/resource/Action.hpp>
11 #include <simgrid/link.h>
13 #include <unordered_map>
14 #include <xbt/Extendable.hpp>
16 #include <xbt/signal.hpp>
24 extern template class XBT_PUBLIC xbt::Extendable<s4u::Link>;
29 * A Link represents the network facilities between :cpp:class:`hosts <simgrid::s4u::Host>`.
32 class XBT_PUBLIC Link : public xbt::Extendable<Link> {
34 friend kernel::resource::StandardLinkImpl;
38 // Links are created from the NetZone, and destroyed by their private implementation when the simulation ends
39 explicit Link(kernel::resource::LinkImpl* pimpl) : pimpl_(pimpl) {}
40 virtual ~Link() = default;
41 // The implementation that never changes
42 kernel::resource::LinkImpl* const pimpl_;
44 friend kernel::resource::NetworkAction; // signal comm_state_changed
48 /** Specifies how a given link is shared between concurrent communications */
49 enum class SharingPolicy {
50 /// This policy takes a callback that specifies the maximal capacity as a function of the number of usage. See the
51 /// examples with 'degradation' in their name.
53 /// Pseudo-sharing policy requesting wifi-specific sharing.
55 /// Each link is split in 2, UP and DOWN, one per direction. These links are SHARED.
57 /// The bandwidth is shared between all comms using that link, regardless of their direction.
59 /// Each comm can use the link fully, with no sharing (only a maximum). This is intended to represent the backbone
60 /// links that cannot be saturated by concurrent links, but have a maximal bandwidth.
64 kernel::resource::StandardLinkImpl* get_impl() const;
66 /** \static @brief Retrieve a link from its name */
67 static Link* by_name(const std::string& name);
68 static Link* by_name_or_null(const std::string& name);
70 /** @brief Retrieves the name of that link as a C++ string */
71 const std::string& get_name() const;
72 /** @brief Retrieves the name of that link as a C string */
73 const char* get_cname() const;
75 /** Get/Set the bandwidth of the current Link (in bytes per second) */
76 double get_bandwidth() const;
77 Link* set_bandwidth(double value);
79 /** Get/Set the latency of the current Link (in seconds) */
80 double get_latency() const;
82 * @brief Set link's latency
84 * @param value New latency value (in s)
86 Link* set_latency(double value);
88 * @brief Set latency (string version)
90 * Accepts values with units, such as '1s' or '7ms'.
92 * Full list of accepted units: w (week), d (day), h, s, ms, us, ns, ps.
94 * @throw std::invalid_argument if latency format is incorrect.
96 Link* set_latency(const std::string& value);
98 /** @brief Describes how the link is shared between flows
100 * Note that the NONLINEAR callback is in the critical path of the solver, so it should be fast.
102 Link* set_sharing_policy(SharingPolicy policy, const NonLinearResourceCb& cb = {});
103 SharingPolicy get_sharing_policy() const;
105 /** Setup the profile with states events (ON or OFF). The profile must contain boolean values. */
106 Link* set_state_profile(kernel::profile::Profile* profile);
107 /** Setup the profile with bandwidth events (peak speed changes due to external load).
108 * The profile must contain percentages (value between 0 and 1). */
109 Link* set_bandwidth_profile(kernel::profile::Profile* profile);
110 /** Setup the profile file with latency events (peak latency changes due to external load).
111 * The profile must contain absolute values */
112 Link* set_latency_profile(kernel::profile::Profile* profile);
114 const std::unordered_map<std::string, std::string>* get_properties() const;
115 const char* get_property(const std::string& key) const;
116 Link* set_properties(const std::unordered_map<std::string, std::string>& properties);
117 Link* set_property(const std::string& key, const std::string& value);
120 * @brief Set the number of communications that can shared this link at the same time
122 * Use this method to serialize communication flows going through this link.
123 * Use -1 to set no limit.
125 * @param limit Number of concurrent flows
127 Link* set_concurrency_limit(int limit);
128 int get_concurrency_limit() const;
130 /** @brief Set the level of communication speed of the given host on this wifi link.
132 * The bandwidth of a wifi link for a given host depends on its SNR (signal to noise ratio),
133 * which ultimately depends on the distance between the host and the station and the material between them.
135 * This is modeled in SimGrid by providing several bandwidths to wifi links, one per SNR level (just provide
136 * comma-separated values in the XML file). By default, the first level in the list is used, but you can use the
137 * current function to specify that a given host uses another level of bandwidth. This can be used to take the
138 * location of hosts into account, or even to model mobility in your SimGrid simulation.
140 * Note that this function asserts that the link is actually a wifi link
142 * warning: in the case where a 0Mbps data rate should be used, set that rate only once during the
143 * experiment, and don't modify the bandwidth of that host later */
144 void set_host_wifi_rate(const s4u::Host* host, int level) const;
146 /** @brief Returns the current load (in bytes per second) */
147 double get_load() const;
150 XBT_ATTRIB_DEPRECATED_v338("Please use get_load() instead") double get_usage() const { return get_load(); }
153 /** @brief Check if the Link is used (at least one flow uses the link) */
154 bool is_used() const;
156 /** @brief Check if the Link is shared (not a FATPIPE) */
157 bool is_shared() const;
159 /** Turns the link on. */
161 /** Turns the link off. */
163 /** Checks whether the link is on. */
170 static xbt::signal<void(Link&)> on_creation;
171 static xbt::signal<void(Link const&)> on_onoff;
172 xbt::signal<void(Link const&)> on_this_onoff;
173 static xbt::signal<void(Link const&)> on_bandwidth_change;
174 xbt::signal<void(Link const&)> on_this_bandwidth_change;
175 static xbt::signal<void(kernel::resource::NetworkAction&, kernel::resource::Action::State)>
176 on_communication_state_change;
177 static xbt::signal<void(Link const&)> on_destruction;
178 xbt::signal<void(Link const&)> on_this_destruction;
183 /** \static @brief Add a callback fired when a new Link is created */
184 static void on_creation_cb(const std::function<void(Link&)>& cb) { on_creation.connect(cb); }
185 /** \static @brief Add a callback fired when any Link is turned on or off */
186 static void on_onoff_cb(const std::function<void(Link const&)>& cb)
188 on_onoff.connect(cb);
190 /** @brief Add a callback fired when this specific Link is turned on or off */
191 void on_this_onoff_cb(const std::function<void(Link const&)>& cb)
193 on_this_onoff.connect(cb);
195 /** \static @brief Add a callback fired when the bandwidth of any Link changes */
196 static void on_bandwidth_change_cb(const std::function<void(Link const&)>& cb) { on_bandwidth_change.connect(cb); }
197 /** @brief Add a callback fired when the bandwidth of this specific Link changes */
198 void on_this_bandwidth_change_cb(const std::function<void(Link const&)>& cb)
200 on_this_bandwidth_change.connect(cb);
202 /** \static @brief Add a callback fired when a communication changes it state (ready/done/cancel) */
203 static void on_communication_state_change_cb(
204 const std::function<void(kernel::resource::NetworkAction&, kernel::resource::Action::State)>& cb)
206 on_communication_state_change.connect(cb);
208 /** \static @brief Add a callback fired when any Link is destroyed */
209 static void on_destruction_cb(const std::function<void(Link const&)>& cb) { on_destruction.connect(cb); }
210 /** @brief Add a callback fired when this specific Link is destroyed */
211 void on_this_destruction_cb(const std::function<void(Link const&)>& cb)
213 on_this_destruction.connect(cb);
216 XBT_ATTRIB_DEPRECATED_v338("Please use on_onoff_cb() instead") static void on_state_change_cb(
217 const std::function<void(Link const&)>& cb)
219 on_onoff.connect(cb);
225 * A SplitDuplexLink encapsulates the :cpp:class:`links <simgrid::s4u::Link>` which
226 * compose a Split-Duplex link. Remember that a Split-Duplex link is nothing more than
227 * a pair of up/down links.
230 class XBT_PUBLIC SplitDuplexLink : public Link {
232 explicit SplitDuplexLink(kernel::resource::LinkImpl* pimpl) : Link(pimpl) {}
233 /** @brief Get the link direction up*/
234 Link* get_link_up() const;
235 /** @brief Get the link direction down */
236 Link* get_link_down() const;
238 /** \static @brief Retrieve a link from its name */
239 static SplitDuplexLink* by_name(const std::string& name);
244 * Another encapsulation for using links in the :cpp:func:`NetZone::add_route`
246 * When adding a route with split-duplex links, you need to specify the direction of the link
247 * so SimGrid can know exactly which physical link to insert in the route.
249 * For shared/fat-pipe links, use the :cpp:enumerator:`Direction::NONE` since they don't have
250 * the concept of UP/DOWN links.
253 class XBT_PUBLIC LinkInRoute {
255 enum class Direction { UP = 2, DOWN = 1, NONE = 0 };
257 explicit LinkInRoute(const Link* link) : link_(link) {}
258 LinkInRoute(const Link* link, Direction d) : link_(link), direction_(d) {}
260 /** @brief Get direction of this link in the route: UP or DOWN */
261 Direction get_direction() const { return direction_; }
262 /** @brief Get pointer to the link */
263 const Link* get_link() const { return link_; }
267 Direction direction_ = Direction::NONE;
271 } // namespace simgrid
273 #endif /* S4U_LINK_HPP */