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 enum class SharingPolicy { NONLINEAR = 4, WIFI = 3, SPLITDUPLEX = 2, SHARED = 1, FATPIPE = 0 };
50 kernel::resource::StandardLinkImpl* get_impl() const;
52 /** @brief Retrieve a link from its name */
53 static Link* by_name(const std::string& name);
54 static Link* by_name_or_null(const std::string& name);
56 /** @brief Retrieves the name of that link as a C++ string */
57 const std::string& get_name() const;
58 /** @brief Retrieves the name of that link as a C string */
59 const char* get_cname() const;
61 /** Get/Set the bandwidth of the current Link (in bytes per second) */
62 double get_bandwidth() const;
63 Link* set_bandwidth(double value);
65 /** Get/Set the latency of the current Link (in seconds) */
66 double get_latency() const;
68 * @brief Set link's latency
70 * @param value New latency value (in s)
72 Link* set_latency(double value);
74 * @brief Set latency (string version)
76 * Accepts values with units, such as '1s' or '7ms'.
78 * Full list of accepted units: w (week), d (day), h, s, ms, us, ns, ps.
80 * @throw std::invalid_argument if latency format is incorrect.
82 Link* set_latency(const std::string& value);
84 /** @brief Describes how the link is shared between flows
86 * Note that the NONLINEAR callback is in the critical path of the solver, so it should be fast.
88 Link* set_sharing_policy(SharingPolicy policy, const NonLinearResourceCb& cb = {});
89 SharingPolicy get_sharing_policy() const;
91 /** Setup the profile with states events (ON or OFF). The profile must contain boolean values. */
92 Link* set_state_profile(kernel::profile::Profile* profile);
93 /** Setup the profile with bandwidth events (peak speed changes due to external load).
94 * The profile must contain percentages (value between 0 and 1). */
95 Link* set_bandwidth_profile(kernel::profile::Profile* profile);
96 /** Setup the profile file with latency events (peak latency changes due to external load).
97 * The profile must contain absolute values */
98 Link* set_latency_profile(kernel::profile::Profile* profile);
100 const std::unordered_map<std::string, std::string>* get_properties() const;
101 const char* get_property(const std::string& key) const;
102 Link* set_properties(const std::unordered_map<std::string, std::string>& properties);
103 Link* set_property(const std::string& key, const std::string& value);
106 * @brief Set the number of communications that can shared this link at the same time
108 * Use this method to serialize communication flows going through this link.
109 * Use -1 to set no limit.
111 * @param limit Number of concurrent flows
113 Link* set_concurrency_limit(int limit);
114 int get_concurrency_limit() const;
116 /** @brief Set the level of communication speed of the given host on this wifi link.
118 * The bandwidth of a wifi link for a given host depends on its SNR (signal to noise ratio),
119 * which ultimately depends on the distance between the host and the station and the material between them.
121 * This is modeled in SimGrid by providing several bandwidths to wifi links, one per SNR level (just provide
122 * comma-separated values in the XML file). By default, the first level in the list is used, but you can use the
123 * current function to specify that a given host uses another level of bandwidth. This can be used to take the
124 * location of hosts into account, or even to model mobility in your SimGrid simulation.
126 * Note that this function asserts that the link is actually a wifi link
128 * warning: in the case where a 0Mbps data rate should be used, set that rate only once during the
129 * experiment, and don't modify the bandwidth of that host later */
130 void set_host_wifi_rate(const s4u::Host* host, int level) const;
132 /** @brief Returns the current load (in bytes per second) */
133 double get_usage() const;
135 /** @brief Check if the Link is used (at least one flow uses the link) */
136 bool is_used() const;
138 /** @brief Check if the Link is shared (not a FATPIPE) */
139 bool is_shared() const;
141 /** Turns the link on. */
143 /** Turns the link off. */
145 /** Checks whether the link is on. */
152 static xbt::signal<void(Link&)> on_creation;
153 static xbt::signal<void(Link const&)> on_state_change;
154 static xbt::signal<void(Link const&)> on_bandwidth_change;
155 static xbt::signal<void(kernel::resource::NetworkAction&, kernel::resource::Action::State)>
156 on_communication_state_change;
157 static xbt::signal<void(Link const&)> on_destruction;
162 /** @brief Add a callback fired when a new Link is created */
163 static void on_creation_cb(const std::function<void(Link&)>& cb) { on_creation.connect(cb); }
164 /** @brief Add a callback fired when the state of a Link changes (when it is turned on or off) */
165 static void on_state_change_cb(const std::function<void(Link const&)>& cb) { on_state_change.connect(cb); }
166 /** @brief Add a callback fired when the bandwidth of a Link changes */
167 static void on_bandwidth_change_cb(const std::function<void(Link const&)>& cb) { on_bandwidth_change.connect(cb); }
168 /** @brief Add a callback fired when a communication changes it state (ready/done/cancel) */
169 static void on_communication_state_change_cb(
170 const std::function<void(kernel::resource::NetworkAction&, kernel::resource::Action::State)>& cb)
172 on_communication_state_change.connect(cb);
174 /** @brief Add a callback fired when a Link is destroyed */
175 static void on_destruction_cb(const std::function<void(Link const&)>& cb) { on_destruction.connect(cb); }
180 * A SplitDuplexLink encapsulates the :cpp:class:`links <simgrid::s4u::Link>` which
181 * compose a Split-Duplex link. Remember that a Split-Duplex link is nothing more than
182 * a pair of up/down links.
185 class XBT_PUBLIC SplitDuplexLink : public Link {
187 explicit SplitDuplexLink(kernel::resource::LinkImpl* pimpl) : Link(pimpl) {}
188 /** @brief Get the link direction up*/
189 Link* get_link_up() const;
190 /** @brief Get the link direction down */
191 Link* get_link_down() const;
193 /** @brief Retrieve a link from its name */
194 static SplitDuplexLink* by_name(const std::string& name);
199 * Another encapsulation for using links in the :cpp:func:`NetZone::add_route`
201 * When adding a route with split-duplex links, you need to specify the direction of the link
202 * so SimGrid can know exactly which physical link to insert in the route.
204 * For shared/fat-pipe links, use the :cpp:enumerator:`Direction::NONE` since they don't have
205 * the concept of UP/DOWN links.
208 class XBT_PUBLIC LinkInRoute {
210 enum class Direction { UP = 2, DOWN = 1, NONE = 0 };
212 explicit LinkInRoute(const Link* link) : link_(link) {}
213 LinkInRoute(const Link* link, Direction d) : link_(link), direction_(d) {}
215 /** @brief Get direction of this link in the route: UP or DOWN */
216 Direction get_direction() const { return direction_; }
217 /** @brief Get pointer to the link */
218 const Link* get_link() const { return link_; }
222 Direction direction_ = Direction::NONE;
226 } // namespace simgrid
228 #endif /* S4U_LINK_HPP */