1 /* Copyright (c) 2010-2022. 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/plugins/load.h>
7 #include <simgrid/s4u/Engine.hpp>
8 #include <simgrid/s4u/Exec.hpp>
9 #include <simgrid/s4u/Host.hpp>
10 #include <simgrid/s4u/VirtualMachine.hpp>
12 #include "src/kernel/activity/ExecImpl.hpp"
13 #include "src/surf/surf_interface.hpp"
15 // Makes sure that this plugin can be activated from the command line with ``--cfg=plugin:host_load``
16 SIMGRID_REGISTER_PLUGIN(host_load, "Cpu load", &sg_host_load_plugin_init)
18 /** @defgroup plugin_host_load Simple plugin that monitors the current load for each host.
21 In addition, this constitutes a good introductory example on how to write a plugin.
22 It attaches an extension to each host to store some data, and places callbacks in the following signals:
24 - :cpp:func:`simgrid::s4u::Host::on_creation_cb`: Attach a new extension to the newly created host.
25 - :cpp:func:`simgrid::s4u::Exec::on_start_cb`: Make note that a new execution started, increasing the load.
26 - :cpp:func:`simgrid::s4u::Exec::on_completion_cb`: Make note that an execution completed, decreasing the load.
27 - :cpp:func:`simgrid::s4u::Host::on_state_change_cb`: Do what is appropriate when the host gets suspended, turned off
29 - :cpp:func:`simgrid::s4u::Host::on_speed_change_cb`: Do what is appropriate when the DVFS is modified.
31 Note that extensions are automatically destroyed when the host gets destroyed.
35 XBT_LOG_NEW_DEFAULT_SUBCATEGORY(host_load, kernel, "Logging specific to the HostLoad plugin");
37 namespace simgrid::plugin {
39 static const double activity_uninitialized_remaining_cost = -1;
41 /** This class stores the extra data needed by this plugin about a given host
43 * It is stored as an extension of s4u::Host. Such extensions are retrieved by type as follows:
46 * simgrid::s4u::Host* this_host = ???;
47 * this_extension = host->extension<HostLoad>();
50 * If no extension of that type was ever attached to the inspected object, the ``extension<X>()`` template returns
53 * Please refer to the implementation of ``sg_host_load_plugin_init()`` to see the extension objects are attached to
54 * hosts at initialization time.
58 static simgrid::xbt::Extension<simgrid::s4u::Host, HostLoad> EXTENSION_ID;
60 explicit HostLoad(simgrid::s4u::Host* ptr)
62 , last_updated_(simgrid_get_clock())
63 , last_reset_(simgrid_get_clock())
64 , current_speed_(host_->get_speed())
65 , current_flops_(host_->get_load())
69 explicit HostLoad(simgrid::s4u::Host& ptr) = delete;
70 explicit HostLoad(simgrid::s4u::Host&& ptr) = delete;
72 double get_current_load() const;
73 /** Get the the average load since last reset(), as a ratio
75 * That's the ratio (amount of flops that were actually computed) / (amount of flops that could have been computed at full speed)
77 double get_average_load() { update(); return (theor_max_flops_ == 0) ? 0 : computed_flops_ / theor_max_flops_; };
78 /** Amount of flops computed since last reset() */
79 double get_computed_flops() { update(); return computed_flops_; }
80 /** Return idle time since last reset() */
81 double get_idle_time() { update(); return idle_time_; }
82 /** Return idle time over the whole simulation */
83 double get_total_idle_time() { update(); return total_idle_time_; }
85 void add_activity(simgrid::kernel::activity::ExecImpl* activity);
89 simgrid::s4u::Host* host_ = nullptr;
90 /* Stores all currently ongoing activities (computations) on this machine */
91 std::map<simgrid::kernel::activity::ExecImpl*, /* cost still remaining*/ double> current_activities;
92 double last_updated_ = 0;
93 double last_reset_ = 0;
95 * current_speed each core is running at; we need to store this as the speed
96 * will already have changed once we get notified
98 double current_speed_ = 0;
100 * How many flops are currently used by all the processes running on this
103 double current_flops_ = 0;
104 double computed_flops_ = 0;
105 double idle_time_ = 0;
106 double total_idle_time_ = 0; /* This updated but never gets reset */
107 double theor_max_flops_ = 0;
110 // Create the static field that the extension mechanism needs
111 simgrid::xbt::Extension<simgrid::s4u::Host, HostLoad> HostLoad::EXTENSION_ID;
113 void HostLoad::add_activity(simgrid::kernel::activity::ExecImpl* activity)
115 current_activities.insert({activity, activity_uninitialized_remaining_cost});
118 void HostLoad::update()
120 double now = simgrid_get_clock();
122 // This loop updates the flops that the host executed for the ongoing computations
123 auto iter = begin(current_activities);
124 while (iter != end(current_activities)) {
125 auto& activity = iter->first; // Just an alias
126 auto& remaining_cost_after_last_update = iter->second; // Just an alias
127 auto& action = activity->surf_action_;
128 auto current_iter = iter;
131 if (action != nullptr && action->get_finish_time() != now &&
132 activity->get_state() == kernel::activity::State::RUNNING) {
133 if (remaining_cost_after_last_update == activity_uninitialized_remaining_cost) {
134 remaining_cost_after_last_update = action->get_cost();
136 double computed_flops_since_last_update = remaining_cost_after_last_update - /*remaining now*/activity->get_remaining();
137 computed_flops_ += computed_flops_since_last_update;
138 remaining_cost_after_last_update = activity->get_remaining();
139 } else if (activity->get_state() == kernel::activity::State::DONE) {
140 computed_flops_ += remaining_cost_after_last_update;
141 current_activities.erase(current_iter);
145 /* Current flop per second computed by the cpu; current_flops = k * pstate_speed_in_flops, k @in {0, 1, ..., cores-1}
146 * designates number of active cores; will be 0 if CPU is currently idle */
147 current_flops_ = host_->get_load();
149 if (current_flops_ == 0) {
150 idle_time_ += (now - last_updated_);
151 total_idle_time_ += (now - last_updated_);
152 XBT_DEBUG("[%s]: Currently idle -> Added %f seconds to idle time (totaling %fs)", host_->get_cname(), (now - last_updated_), idle_time_);
155 theor_max_flops_ += current_speed_ * host_->get_core_count() * (now - last_updated_);
156 current_speed_ = host_->get_speed();
160 /** @brief Get the current load as a ratio = achieved_flops / (core_current_speed * core_amount)
162 * You may also want to check simgrid::s4u::Host::get_load() that simply returns
163 * the achieved flop rate (in flops per seconds), ie the load that a new action arriving on
164 * that host would suffer.
166 * Please note that this function only returns an instantaneous load that may be deceiving
167 * in some scenarios. For example, imagine that an activity terminates at time t, and that
168 * another activity is created on the same host at the exact same timestamp. The load was
169 * never 0 on the simulated machine since the time did not advance between the two events.
170 * But still, if you call this function between the two events (in the simulator course), it
171 * returns 0 although there is no time (in the simulated time) where this value is valid.
173 double HostLoad::get_current_load() const
175 // We don't need to call update() here because it is called every time an action terminates or starts
176 return current_flops_ / (host_->get_speed() * host_->get_core_count());
180 * Resets the counters
182 void HostLoad::reset()
184 last_updated_ = simgrid_get_clock();
185 last_reset_ = simgrid_get_clock();
188 theor_max_flops_ = 0;
189 current_flops_ = host_->get_load();
190 current_speed_ = host_->get_speed();
192 } // namespace simgrid::plugin
194 using simgrid::plugin::HostLoad;
196 /* **************************** events callback *************************** */
197 /* This callback is fired either when the host changes its state (on/off) or its speed
198 * (because the user changed the pstate, or because of external trace events) */
199 static void on_host_change(simgrid::s4u::Host const& host)
201 if (dynamic_cast<simgrid::s4u::VirtualMachine const*>(&host)) // Ignore virtual machines
204 host.extension<HostLoad>()->update();
207 /* **************************** Public interface *************************** */
209 /** @brief Initializes the HostLoad plugin
210 * @ingroup plugin_host_load
212 void sg_host_load_plugin_init()
214 if (HostLoad::EXTENSION_ID.valid()) // Don't do the job twice
217 // First register our extension of Hosts properly
218 HostLoad::EXTENSION_ID = simgrid::s4u::Host::extension_create<HostLoad>();
220 // If SimGrid is already initialized, we need to attach an extension to each existing host
221 if (simgrid::s4u::Engine::is_initialized()) {
222 const simgrid::s4u::Engine* e = simgrid::s4u::Engine::get_instance();
223 for (auto& host : e->get_all_hosts()) {
224 host->extension_set(new HostLoad(host));
228 // Make sure that every future host also gets an extension (in case the platform is not loaded yet)
229 simgrid::s4u::Host::on_creation_cb([](simgrid::s4u::Host& host) {
230 if (dynamic_cast<simgrid::s4u::VirtualMachine*>(&host)) // Ignore virtual machines
232 host.extension_set(new HostLoad(&host));
235 simgrid::s4u::Exec::on_start_cb([](simgrid::s4u::Exec const& activity) {
236 if (activity.get_host_number() == 1) { // We only run on one host
237 simgrid::s4u::Host* host = activity.get_host();
238 if (const auto* vm = dynamic_cast<simgrid::s4u::VirtualMachine*>(host))
240 xbt_assert(host != nullptr);
241 host->extension<HostLoad>()->add_activity(static_cast<simgrid::kernel::activity::ExecImpl*>(activity.get_impl()));
242 host->extension<HostLoad>()->update(); // If the system was idle until now, we need to update *before*
243 // this computation starts running so we can keep track of the
244 // idle time. (Communication operations don't trigger this hook!)
246 else { // This runs on multiple hosts
247 XBT_WARN("HostLoad plugin currently does not support executions on several hosts");
250 simgrid::s4u::Activity::on_completion_cb([](simgrid::s4u::Activity const& activity) {
251 const auto* exec = dynamic_cast<simgrid::s4u::Exec const*>(&activity);
252 if (exec == nullptr) // Only Execs are concerned here
254 if (exec->get_host_number() == 1) { // We only run on one host
255 simgrid::s4u::Host* host = exec->get_host();
256 if (const auto* vm = dynamic_cast<simgrid::s4u::VirtualMachine*>(host))
258 xbt_assert(host != nullptr);
259 host->extension<HostLoad>()->update();
260 } else { // This runs on multiple hosts
261 XBT_WARN("HostLoad plugin currently does not support executions on several hosts");
264 simgrid::s4u::Host::on_state_change_cb(&on_host_change);
265 simgrid::s4u::Host::on_speed_change_cb(&on_host_change);
268 /** @brief Returns the current load of that host, as a ratio = achieved_flops / (core_current_speed * core_amount)
269 * @ingroup plugin_host_load
271 double sg_host_get_current_load(const_sg_host_t host)
273 xbt_assert(HostLoad::EXTENSION_ID.valid(), "Please sg_host_load_plugin_init() to initialize this plugin.");
275 return host->extension<HostLoad>()->get_current_load();
278 /** @brief Returns the current load of that host
279 * @ingroup plugin_host_load
281 double sg_host_get_avg_load(const_sg_host_t host)
283 xbt_assert(HostLoad::EXTENSION_ID.valid(), "Please sg_host_load_plugin_init() to initialize this plugin.");
285 return host->extension<HostLoad>()->get_average_load();
288 /** @brief Returns the time this host was idle since the last reset
289 * @ingroup plugin_host_load
291 double sg_host_get_idle_time(const_sg_host_t host)
293 xbt_assert(HostLoad::EXTENSION_ID.valid(), "Please sg_host_load_plugin_init() to initialize this plugin.");
295 return host->extension<HostLoad>()->get_idle_time();
298 /** @brief Returns the time this host was idle since the beginning of the simulation
299 * @ingroup plugin_host_load
301 double sg_host_get_total_idle_time(const_sg_host_t host)
303 xbt_assert(HostLoad::EXTENSION_ID.valid(), "Please sg_host_load_plugin_init() to initialize this plugin.");
305 return host->extension<HostLoad>()->get_total_idle_time();
308 /** @brief Returns the amount of flops computed by that host since the last reset
309 * @ingroup plugin_host_load
311 double sg_host_get_computed_flops(const_sg_host_t host)
313 xbt_assert(HostLoad::EXTENSION_ID.valid(), "Please sg_host_load_plugin_init() to initialize this plugin.");
315 return host->extension<HostLoad>()->get_computed_flops();
318 /** @brief Resets the idle time and flops amount of that host
319 * @ingroup plugin_host_load
321 void sg_host_load_reset(const_sg_host_t host)
323 xbt_assert(HostLoad::EXTENSION_ID.valid(), "Please sg_host_load_plugin_init() to initialize this plugin.");
325 host->extension<HostLoad>()->reset();