1 /* Copyright (c) 2019-2020. 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. */
6 #include "network_wifi.hpp"
7 #include "simgrid/s4u/Host.hpp"
8 #include "src/surf/surf_interface.hpp"
10 XBT_LOG_EXTERNAL_DEFAULT_CATEGORY(surf_network);
20 NetworkWifiLink::NetworkWifiLink(NetworkCm02Model* model, const std::string& name, std::vector<double> bandwidths,
22 : LinkImpl(model, name, system->constraint_new(this, 1))
24 for (auto bandwidth : bandwidths)
25 bandwidths_.push_back({bandwidth, 1.0, nullptr});
27 simgrid::s4u::Link::on_creation(*get_iface());
30 void NetworkWifiLink::set_host_rate(const s4u::Host* host, int rate_level)
32 auto insert_done = host_rates_.insert(std::make_pair(host->get_name(), rate_level));
33 if (not insert_done.second)
34 insert_done.first->second = rate_level;
36 // Each time we add a host, we refresh the decay model
37 refresh_decay_bandwidths();
40 double NetworkWifiLink::get_host_rate(const s4u::Host* host) const
42 auto host_rates_it = host_rates_.find(host->get_name());
44 if (host_rates_it == host_rates_.end())
47 int rate_id = host_rates_it->second;
48 xbt_assert(rate_id >= 0,
49 "Negative host wifi rate levels are invalid but host '%s' uses %d as a rate level on link '%s'",
50 host->get_cname(), rate_id, this->get_cname());
51 xbt_assert(rate_id < (int)bandwidths_.size(),
52 "Link '%s' only has %zu wifi rate levels, so the provided level %d is invalid for host '%s'.",
53 this->get_cname(), bandwidths_.size(), rate_id, host->get_cname());
55 Metric rate = use_decay_model_ ? decay_bandwidths_[rate_id] : bandwidths_[rate_id];
56 return rate.peak * rate.scale;
59 s4u::Link::SharingPolicy NetworkWifiLink::get_sharing_policy() const
61 return s4u::Link::SharingPolicy::WIFI;
64 int NetworkWifiLink::get_host_count() const
66 return static_cast<int>(host_rates_.size());
69 void NetworkWifiLink::refresh_decay_bandwidths(){
70 // Compute number of STAtion on the Access Point
71 int nSTA = get_host_count();
73 std::vector<Metric> new_bandwidths;
74 for (auto bandwidth : bandwidths_){
75 // Instantiate decay model relatively to the actual bandwidth
76 double max_bw=bandwidth.peak;
77 double min_bw=bandwidth.peak-(wifi_max_rate_-wifi_min_rate_);
78 double model_rate=bandwidth.peak-(wifi_max_rate_-model_rate_);
80 xbt_assert(min_bw > 0, "Your WIFI link is using bandwidth(s) which is too low for the decay model.");
82 double N0=max_bw-min_bw;
83 double lambda=(-log(model_rate-min_bw)+log(N0))/model_n_;
84 // Since decay model start at 0 we should use (nSTA-1)
85 double new_peak=N0*exp(-lambda*(nSTA-1))+min_bw;
86 new_bandwidths.push_back({new_peak, 1.0, nullptr});
88 decay_bandwidths_=new_bandwidths;
91 bool NetworkWifiLink::toggle_decay_model(){
92 use_decay_model_=!use_decay_model_;
93 return(use_decay_model_);
97 } // namespace resource
99 } // namespace simgrid