1 /* Copyright (c) 2019-2021. 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(res_network);
20 NetworkWifiLink::NetworkWifiLink(const std::string& name, std::vector<double> bandwidths, lmm::System* system)
21 : LinkImpl(name, system->constraint_new(this, 1))
23 for (auto bandwidth : bandwidths)
24 bandwidths_.push_back({bandwidth, 1.0, nullptr});
27 void NetworkWifiLink::set_host_rate(const s4u::Host* host, int rate_level)
29 auto insert_done = host_rates_.insert(std::make_pair(host->get_name(), rate_level));
30 if (not insert_done.second)
31 insert_done.first->second = rate_level;
33 // Each time we add a host, we refresh the decay model
34 refresh_decay_bandwidths();
37 double NetworkWifiLink::get_host_rate(const s4u::Host* host) const
39 auto host_rates_it = host_rates_.find(host->get_name());
41 if (host_rates_it == host_rates_.end())
44 int rate_id = host_rates_it->second;
45 xbt_assert(rate_id >= 0,
46 "Negative host wifi rate levels are invalid but host '%s' uses %d as a rate level on link '%s'",
47 host->get_cname(), rate_id, this->get_cname());
48 xbt_assert(rate_id < (int)bandwidths_.size(),
49 "Link '%s' only has %zu wifi rate levels, so the provided level %d is invalid for host '%s'.",
50 this->get_cname(), bandwidths_.size(), rate_id, host->get_cname());
52 Metric rate = use_decay_model_ ? decay_bandwidths_[rate_id] : bandwidths_[rate_id];
53 return rate.peak * rate.scale;
56 s4u::Link::SharingPolicy NetworkWifiLink::get_sharing_policy() const
58 return s4u::Link::SharingPolicy::WIFI;
61 int NetworkWifiLink::get_host_count() const
63 return static_cast<int>(host_rates_.size());
66 void NetworkWifiLink::refresh_decay_bandwidths(){
67 // Compute number of STAtion on the Access Point
68 int nSTA = get_host_count();
70 std::vector<Metric> new_bandwidths;
71 for (auto const& bandwidth : bandwidths_) {
72 // Instantiate decay model relatively to the actual bandwidth
73 double max_bw=bandwidth.peak;
74 double min_bw=bandwidth.peak-(wifi_max_rate_-wifi_min_rate_);
75 double model_rate=bandwidth.peak-(wifi_max_rate_-model_rate_);
77 xbt_assert(min_bw > 0, "Your WIFI link is using bandwidth(s) which is too low for the decay model.");
79 double N0=max_bw-min_bw;
80 double lambda=(-log(model_rate-min_bw)+log(N0))/model_n_;
81 // Since decay model start at 0 we should use (nSTA-1)
82 double new_peak=N0*exp(-lambda*(nSTA-1))+min_bw;
83 new_bandwidths.push_back({new_peak, 1.0, nullptr});
85 decay_bandwidths_=new_bandwidths;
88 bool NetworkWifiLink::toggle_decay_model(){
89 use_decay_model_=!use_decay_model_;
90 return(use_decay_model_);
94 } // namespace resource
96 } // namespace simgrid