1 /* Copyright (c) 2010-2018. 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 <simgrid/s4u.hpp>
7 #include "simgrid/plugins/load.h"
8 #include "src/plugins/vm/VirtualMachineImpl.hpp"
10 /** @addtogroup plugin_load
12 This plugin makes it very simple for users to obtain the current load for each host.
16 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(surf_plugin_load, surf, "Logging specific to the HostLoad plugin");
23 static simgrid::xbt::Extension<simgrid::s4u::Host, HostLoad> EXTENSION_ID;
25 explicit HostLoad(simgrid::s4u::Host* ptr)
27 , last_updated_(surf_get_clock())
28 , last_reset_(surf_get_clock())
29 , current_speed_(host_->getSpeed())
30 , current_flops_(host_->pimpl_cpu->get_constraint()->get_usage())
32 , was_prev_idle_(current_flops_ == 0)
35 ~HostLoad() = default;
37 explicit HostLoad(simgrid::s4u::Host& ptr) = delete;
38 explicit HostLoad(simgrid::s4u::Host&& ptr) = delete;
40 double get_current_load();
41 double get_average_load() { return (theor_max_flops_ == 0) ? 0 : computed_flops_ / theor_max_flops_; };
42 double get_computed_flops() { return computed_flops_; }
43 double get_idle_time() { return idle_time_; } /** Return idle time since last reset */
48 simgrid::s4u::Host* host_ = nullptr;
49 double last_updated_ = 0;
50 double last_reset_ = 0;
52 * current_speed each core is running at right now
54 double current_speed_ = 0;
56 * How many flops are currently used by all the processes running on this
59 double current_flops_ = 0;
60 double computed_flops_ = 0;
61 double idle_time_ = 0;
62 double theor_max_flops_ = 0;
63 bool was_prev_idle_ = true; /* A host is idle at the beginning */
66 simgrid::xbt::Extension<simgrid::s4u::Host, HostLoad> HostLoad::EXTENSION_ID;
68 void HostLoad::update()
70 double now = surf_get_clock();
72 /* Current flop per second computed by the cpu; current_flops = k * pstate_speed_in_flops, k \in {0, 1, ..., cores}
73 * number of active cores */
74 current_flops_ = host_->pimpl_cpu->get_constraint()->get_usage();
76 /* flops == pstate_speed * cores_being_currently_used */
77 computed_flops_ += (now - last_updated_) * current_flops_;
80 idle_time_ += (now - last_updated_);
83 theor_max_flops_ += current_speed_ * host_->get_core_count() * (now - last_updated_);
84 current_speed_ = host_->getSpeed();
86 was_prev_idle_ = (current_flops_ == 0);
90 * WARNING: This function does not guarantee that you have the real load at any time imagine all actions on your CPU
91 * terminate at time t. Your load is then 0. Then you query the load (still 0) and then another action starts (still at
92 * time t!). This means that the load was never really 0 (because the time didn't advance) but it will still be reported
95 * So, use at your own risk.
97 double HostLoad::get_current_load()
99 // We don't need to call update() here because it is called every time an action terminates or starts
100 // FIXME: Can this happen at the same time? stop -> call to getCurrentLoad, load = 0 -> next action starts?
101 return current_flops_ / static_cast<double>(host_->getSpeed() * host_->get_core_count());
105 * Resets the counters
107 void HostLoad::reset()
109 last_updated_ = surf_get_clock();
110 last_reset_ = surf_get_clock();
113 theor_max_flops_ = 0;
114 current_flops_ = host_->pimpl_cpu->get_constraint()->get_usage();
115 current_speed_ = host_->getSpeed();
116 was_prev_idle_ = (current_flops_ == 0);
118 } // namespace plugin
119 } // namespace simgrid
121 using simgrid::plugin::HostLoad;
123 /* **************************** events callback *************************** */
124 /* This callback is fired either when the host changes its state (on/off) or its speed
125 * (because the user changed the pstate, or because of external trace events) */
126 static void on_host_change(simgrid::s4u::Host& host)
128 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(&host)) // Ignore virtual machines
131 host.extension<HostLoad>()->update();
134 /* This callback is called when an action (computation, idle, ...) terminates */
135 static void on_action_state_change(simgrid::surf::CpuAction* action)
137 for (simgrid::surf::Cpu* const& cpu : action->cpus()) {
138 simgrid::s4u::Host* host = cpu->get_host();
140 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(host)) // Ignore virtual machines
143 if (host != nullptr) {
144 host->extension<HostLoad>()->update();
149 /* **************************** Public interface *************************** */
151 /** \ingroup plugin_load
152 * \brief Initializes the HostLoad plugin
153 * \details The HostLoad plugin provides an API to get the current load of each host.
155 void sg_host_load_plugin_init()
157 if (HostLoad::EXTENSION_ID.valid())
160 HostLoad::EXTENSION_ID = simgrid::s4u::Host::extension_create<HostLoad>();
162 if (simgrid::s4u::Engine::is_initialized()) { // If not yet initialized, this would create a new instance
163 // which would cause seg faults...
164 simgrid::s4u::Engine* e = simgrid::s4u::Engine::get_instance();
165 for (auto& host : e->get_all_hosts()) {
166 host->extension_set(new HostLoad(host));
170 /* When attaching a callback into a signal, you can use a lambda as follows, or a regular function as done below */
172 simgrid::s4u::Host::on_creation.connect([](simgrid::s4u::Host& host) {
173 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(&host)) // Ignore virtual machines
175 host.extension_set(new HostLoad(&host));
178 simgrid::surf::CpuAction::on_state_change.connect(&on_action_state_change);
179 simgrid::s4u::Host::on_state_change.connect(&on_host_change);
180 simgrid::s4u::Host::on_speed_change.connect(&on_host_change);
183 /** @brief Returns the current load of the host passed as argument
185 * See also @ref plugin_load
187 double sg_host_get_current_load(sg_host_t host)
189 xbt_assert(HostLoad::EXTENSION_ID.valid(),
190 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
192 return host->extension<HostLoad>()->get_current_load();
195 /** @brief Returns the current load of the host passed as argument
197 * See also @ref plugin_load
199 double sg_host_get_avg_load(sg_host_t host)
201 xbt_assert(HostLoad::EXTENSION_ID.valid(),
202 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
204 return host->extension<HostLoad>()->get_average_load();
207 /** @brief Returns the time this host was idle since the last reset
209 * See also @ref plugin_load
211 double sg_host_get_idle_time(sg_host_t host)
213 xbt_assert(HostLoad::EXTENSION_ID.valid(),
214 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
216 return host->extension<HostLoad>()->get_idle_time();
219 double sg_host_get_computed_flops(sg_host_t host)
221 xbt_assert(HostLoad::EXTENSION_ID.valid(),
222 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
224 return host->extension<HostLoad>()->get_computed_flops();
227 void sg_host_load_reset(sg_host_t host)
229 xbt_assert(HostLoad::EXTENSION_ID.valid(),
230 "The Load plugin is not active. Please call sg_host_load_plugin_init() during initialization.");
232 host->extension<HostLoad>()->reset();